parsenodes.h

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/*-------------------------------------------------------------------------
 *
 * parsenodes.h
 *    definitions for parse tree nodes
 *
 * Many of the node types used in parsetrees include a "location" field.
 * This is a byte (not character) offset in the original source text, to be
 * used for positioning an error cursor when there is an error related to
 * the node.  Access to the original source text is needed to make use of
 * the location.
 *
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/nodes/parsenodes.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PARSENODES_H
#define PARSENODES_H

#include "nodes/bitmapset.h"
#include "nodes/primnodes.h"
#include "nodes/value.h"

/* Possible sources of a Query */
typedef enum QuerySource
{
    QSRC_ORIGINAL,              /* original parsetree (explicit query) */
    QSRC_PARSER,                /* added by parse analysis (now unused) */
    QSRC_INSTEAD_RULE,          /* added by unconditional INSTEAD rule */
    QSRC_QUAL_INSTEAD_RULE,     /* added by conditional INSTEAD rule */
    QSRC_NON_INSTEAD_RULE       /* added by non-INSTEAD rule */
} QuerySource;

/* Sort ordering options for ORDER BY and CREATE INDEX */
typedef enum SortByDir
{
    SORTBY_DEFAULT,
    SORTBY_ASC,
    SORTBY_DESC,
    SORTBY_USING                /* not allowed in CREATE INDEX ... */
} SortByDir;

typedef enum SortByNulls
{
    SORTBY_NULLS_DEFAULT,
    SORTBY_NULLS_FIRST,
    SORTBY_NULLS_LAST
} SortByNulls;

/*
 * Grantable rights are encoded so that we can OR them together in a bitmask.
 * The present representation of AclItem limits us to 16 distinct rights,
 * even though AclMode is defined as uint32.  See utils/acl.h.
 *
 * Caution: changing these codes breaks stored ACLs, hence forces initdb.
 */
typedef uint32 AclMode;         /* a bitmask of privilege bits */

#define ACL_INSERT      (1<<0)  /* for relations */
#define ACL_SELECT      (1<<1)
#define ACL_UPDATE      (1<<2)
#define ACL_DELETE      (1<<3)
#define ACL_TRUNCATE    (1<<4)
#define ACL_REFERENCES  (1<<5)
#define ACL_TRIGGER     (1<<6)
#define ACL_EXECUTE     (1<<7)  /* for functions */
#define ACL_USAGE       (1<<8)  /* for languages, namespaces, FDWs, and
                                 * servers */
#define ACL_CREATE      (1<<9)  /* for namespaces and databases */
#define ACL_CREATE_TEMP (1<<10) /* for databases */
#define ACL_CONNECT     (1<<11) /* for databases */
#define N_ACL_RIGHTS    12      /* 1 plus the last 1<<x */
#define ACL_NO_RIGHTS   0
/* Currently, SELECT ... FOR [KEY] UPDATE/SHARE requires UPDATE privileges */
#define ACL_SELECT_FOR_UPDATE   ACL_UPDATE


/*****************************************************************************
 *  Query Tree
 *****************************************************************************/

/*
 * Query -
 *    Parse analysis turns all statements into a Query tree
 *    for further processing by the rewriter and planner.
 *
 *    Utility statements (i.e. non-optimizable statements) have the
 *    utilityStmt field set, and the Query itself is mostly dummy.
 *    DECLARE CURSOR is a special case: it is represented like a SELECT,
 *    but the original DeclareCursorStmt is stored in utilityStmt.
 *
 *    Planning converts a Query tree into a Plan tree headed by a PlannedStmt
 *    node --- the Query structure is not used by the executor.
 */
typedef struct Query
{
    NodeTag     type;

    CmdType     commandType;    /* select|insert|update|delete|utility */

    QuerySource querySource;    /* where did I come from? */

    uint32      queryId;        /* query identifier (can be set by plugins) */

    bool        canSetTag;      /* do I set the command result tag? */

    Node       *utilityStmt;    /* non-null if this is DECLARE CURSOR or a
                                 * non-optimizable statement */

    int         resultRelation; /* rtable index of target relation for
                                 * INSERT/UPDATE/DELETE; 0 for SELECT */

    bool        hasAggs;        /* has aggregates in tlist or havingQual */
    bool        hasWindowFuncs; /* has window functions in tlist */
    bool        hasSubLinks;    /* has subquery SubLink */
    bool        hasDistinctOn;  /* distinctClause is from DISTINCT ON */
    bool        hasRecursive;   /* WITH RECURSIVE was specified */
    bool        hasModifyingCTE;    /* has INSERT/UPDATE/DELETE in WITH */
    bool        hasForUpdate;   /* FOR [KEY] UPDATE/SHARE was specified */

    List       *cteList;        /* WITH list (of CommonTableExpr's) */

    List       *rtable;         /* list of range table entries */
    FromExpr   *jointree;       /* table join tree (FROM and WHERE clauses) */

    List       *targetList;     /* target list (of TargetEntry) */

    List       *returningList;  /* return-values list (of TargetEntry) */

    List       *groupClause;    /* a list of SortGroupClause's */

    Node       *havingQual;     /* qualifications applied to groups */

    List       *windowClause;   /* a list of WindowClause's */

    List       *distinctClause; /* a list of SortGroupClause's */

    List       *sortClause;     /* a list of SortGroupClause's */

    Node       *limitOffset;    /* # of result tuples to skip (int8 expr) */
    Node       *limitCount;     /* # of result tuples to return (int8 expr) */

    List       *rowMarks;       /* a list of RowMarkClause's */

    Node       *setOperations;  /* set-operation tree if this is top level of
                                 * a UNION/INTERSECT/EXCEPT query */

    List       *constraintDeps; /* a list of pg_constraint OIDs that the query
                                 * depends on to be semantically valid */
} Query;


/****************************************************************************
 *  Supporting data structures for Parse Trees
 *
 *  Most of these node types appear in raw parsetrees output by the grammar,
 *  and get transformed to something else by the analyzer.  A few of them
 *  are used as-is in transformed querytrees.
 ****************************************************************************/

/*
 * TypeName - specifies a type in definitions
 *
 * For TypeName structures generated internally, it is often easier to
 * specify the type by OID than by name.  If "names" is NIL then the
 * actual type OID is given by typeOid, otherwise typeOid is unused.
 * Similarly, if "typmods" is NIL then the actual typmod is expected to
 * be prespecified in typemod, otherwise typemod is unused.
 *
 * If pct_type is TRUE, then names is actually a field name and we look up
 * the type of that field.  Otherwise (the normal case), names is a type
 * name possibly qualified with schema and database name.
 */
typedef struct TypeName
{
    NodeTag     type;
    List       *names;          /* qualified name (list of Value strings) */
    Oid         typeOid;        /* type identified by OID */
    bool        setof;          /* is a set? */
    bool        pct_type;       /* %TYPE specified? */
    List       *typmods;        /* type modifier expression(s) */
    int32       typemod;        /* prespecified type modifier */
    List       *arrayBounds;    /* array bounds */
    int         location;       /* token location, or -1 if unknown */
} TypeName;

/*
 * ColumnRef - specifies a reference to a column, or possibly a whole tuple
 *
 * The "fields" list must be nonempty.  It can contain string Value nodes
 * (representing names) and A_Star nodes (representing occurrence of a '*').
 * Currently, A_Star must appear only as the last list element --- the grammar
 * is responsible for enforcing this!
 *
 * Note: any array subscripting or selection of fields from composite columns
 * is represented by an A_Indirection node above the ColumnRef.  However,
 * for simplicity in the normal case, initial field selection from a table
 * name is represented within ColumnRef and not by adding A_Indirection.
 */
typedef struct ColumnRef
{
    NodeTag     type;
    List       *fields;         /* field names (Value strings) or A_Star */
    int         location;       /* token location, or -1 if unknown */
} ColumnRef;

/*
 * ParamRef - specifies a $n parameter reference
 */
typedef struct ParamRef
{
    NodeTag     type;
    int         number;         /* the number of the parameter */
    int         location;       /* token location, or -1 if unknown */
} ParamRef;

/*
 * A_Expr - infix, prefix, and postfix expressions
 */
typedef enum A_Expr_Kind
{
    AEXPR_OP,                   /* normal operator */
    AEXPR_AND,                  /* booleans - name field is unused */
    AEXPR_OR,
    AEXPR_NOT,
    AEXPR_OP_ANY,               /* scalar op ANY (array) */
    AEXPR_OP_ALL,               /* scalar op ALL (array) */
    AEXPR_DISTINCT,             /* IS DISTINCT FROM - name must be "=" */
    AEXPR_NULLIF,               /* NULLIF - name must be "=" */
    AEXPR_OF,                   /* IS [NOT] OF - name must be "=" or "<>" */
    AEXPR_IN                    /* [NOT] IN - name must be "=" or "<>" */
} A_Expr_Kind;

typedef struct A_Expr
{
    NodeTag     type;
    A_Expr_Kind kind;           /* see above */
    List       *name;           /* possibly-qualified name of operator */
    Node       *lexpr;          /* left argument, or NULL if none */
    Node       *rexpr;          /* right argument, or NULL if none */
    int         location;       /* token location, or -1 if unknown */
} A_Expr;

/*
 * A_Const - a literal constant
 */
typedef struct A_Const
{
    NodeTag     type;
    Value       val;            /* value (includes type info, see value.h) */
    int         location;       /* token location, or -1 if unknown */
} A_Const;

/*
 * TypeCast - a CAST expression
 */
typedef struct TypeCast
{
    NodeTag     type;
    Node       *arg;            /* the expression being casted */
    TypeName   *typeName;       /* the target type */
    int         location;       /* token location, or -1 if unknown */
} TypeCast;

/*
 * CollateClause - a COLLATE expression
 */
typedef struct CollateClause
{
    NodeTag     type;
    Node       *arg;            /* input expression */
    List       *collname;       /* possibly-qualified collation name */
    int         location;       /* token location, or -1 if unknown */
} CollateClause;

/*
 * FuncCall - a function or aggregate invocation
 *
 * agg_order (if not NIL) indicates we saw 'foo(... ORDER BY ...)'.
 * agg_star indicates we saw a 'foo(*)' construct, while agg_distinct
 * indicates we saw 'foo(DISTINCT ...)'.  In any of these cases, the
 * construct *must* be an aggregate call.  Otherwise, it might be either an
 * aggregate or some other kind of function.  However, if OVER is present
 * it had better be an aggregate or window function.
 */
typedef struct FuncCall
{
    NodeTag     type;
    List       *funcname;       /* qualified name of function */
    List       *args;           /* the arguments (list of exprs) */
    List       *agg_order;      /* ORDER BY (list of SortBy) */
    bool        agg_star;       /* argument was really '*' */
    bool        agg_distinct;   /* arguments were labeled DISTINCT */
    bool        func_variadic;  /* last argument was labeled VARIADIC */
    struct WindowDef *over;     /* OVER clause, if any */
    int         location;       /* token location, or -1 if unknown */
} FuncCall;

/*
 * A_Star - '*' representing all columns of a table or compound field
 *
 * This can appear within ColumnRef.fields, A_Indirection.indirection, and
 * ResTarget.indirection lists.
 */
typedef struct A_Star
{
    NodeTag     type;
} A_Star;

/*
 * A_Indices - array subscript or slice bounds ([lidx:uidx] or [uidx])
 */
typedef struct A_Indices
{
    NodeTag     type;
    Node       *lidx;           /* NULL if it's a single subscript */
    Node       *uidx;
} A_Indices;

/*
 * A_Indirection - select a field and/or array element from an expression
 *
 * The indirection list can contain A_Indices nodes (representing
 * subscripting), string Value nodes (representing field selection --- the
 * string value is the name of the field to select), and A_Star nodes
 * (representing selection of all fields of a composite type).
 * For example, a complex selection operation like
 *              (foo).field1[42][7].field2
 * would be represented with a single A_Indirection node having a 4-element
 * indirection list.
 *
 * Currently, A_Star must appear only as the last list element --- the grammar
 * is responsible for enforcing this!
 */
typedef struct A_Indirection
{
    NodeTag     type;
    Node       *arg;            /* the thing being selected from */
    List       *indirection;    /* subscripts and/or field names and/or * */
} A_Indirection;

/*
 * A_ArrayExpr - an ARRAY[] construct
 */
typedef struct A_ArrayExpr
{
    NodeTag     type;
    List       *elements;       /* array element expressions */
    int         location;       /* token location, or -1 if unknown */
} A_ArrayExpr;

/*
 * ResTarget -
 *    result target (used in target list of pre-transformed parse trees)
 *
 * In a SELECT target list, 'name' is the column label from an
 * 'AS ColumnLabel' clause, or NULL if there was none, and 'val' is the
 * value expression itself.  The 'indirection' field is not used.
 *
 * INSERT uses ResTarget in its target-column-names list.  Here, 'name' is
 * the name of the destination column, 'indirection' stores any subscripts
 * attached to the destination, and 'val' is not used.
 *
 * In an UPDATE target list, 'name' is the name of the destination column,
 * 'indirection' stores any subscripts attached to the destination, and
 * 'val' is the expression to assign.
 *
 * See A_Indirection for more info about what can appear in 'indirection'.
 */
typedef struct ResTarget
{
    NodeTag     type;
    char       *name;           /* column name or NULL */
    List       *indirection;    /* subscripts, field names, and '*', or NIL */
    Node       *val;            /* the value expression to compute or assign */
    int         location;       /* token location, or -1 if unknown */
} ResTarget;

/*
 * SortBy - for ORDER BY clause
 */
typedef struct SortBy
{
    NodeTag     type;
    Node       *node;           /* expression to sort on */
    SortByDir   sortby_dir;     /* ASC/DESC/USING/default */
    SortByNulls sortby_nulls;   /* NULLS FIRST/LAST */
    List       *useOp;          /* name of op to use, if SORTBY_USING */
    int         location;       /* operator location, or -1 if none/unknown */
} SortBy;

/*
 * WindowDef - raw representation of WINDOW and OVER clauses
 *
 * For entries in a WINDOW list, "name" is the window name being defined.
 * For OVER clauses, we use "name" for the "OVER window" syntax, or "refname"
 * for the "OVER (window)" syntax, which is subtly different --- the latter
 * implies overriding the window frame clause.
 */
typedef struct WindowDef
{
    NodeTag     type;
    char       *name;           /* window's own name */
    char       *refname;        /* referenced window name, if any */
    List       *partitionClause;    /* PARTITION BY expression list */
    List       *orderClause;    /* ORDER BY (list of SortBy) */
    int         frameOptions;   /* frame_clause options, see below */
    Node       *startOffset;    /* expression for starting bound, if any */
    Node       *endOffset;      /* expression for ending bound, if any */
    int         location;       /* parse location, or -1 if none/unknown */
} WindowDef;

/*
 * frameOptions is an OR of these bits.  The NONDEFAULT and BETWEEN bits are
 * used so that ruleutils.c can tell which properties were specified and
 * which were defaulted; the correct behavioral bits must be set either way.
 * The START_foo and END_foo options must come in pairs of adjacent bits for
 * the convenience of gram.y, even though some of them are useless/invalid.
 * We will need more bits (and fields) to cover the full SQL:2008 option set.
 */
#define FRAMEOPTION_NONDEFAULT                  0x00001 /* any specified? */
#define FRAMEOPTION_RANGE                       0x00002 /* RANGE behavior */
#define FRAMEOPTION_ROWS                        0x00004 /* ROWS behavior */
#define FRAMEOPTION_BETWEEN                     0x00008 /* BETWEEN given? */
#define FRAMEOPTION_START_UNBOUNDED_PRECEDING   0x00010 /* start is U. P. */
#define FRAMEOPTION_END_UNBOUNDED_PRECEDING     0x00020 /* (disallowed) */
#define FRAMEOPTION_START_UNBOUNDED_FOLLOWING   0x00040 /* (disallowed) */
#define FRAMEOPTION_END_UNBOUNDED_FOLLOWING     0x00080 /* end is U. F. */
#define FRAMEOPTION_START_CURRENT_ROW           0x00100 /* start is C. R. */
#define FRAMEOPTION_END_CURRENT_ROW             0x00200 /* end is C. R. */
#define FRAMEOPTION_START_VALUE_PRECEDING       0x00400 /* start is V. P. */
#define FRAMEOPTION_END_VALUE_PRECEDING         0x00800 /* end is V. P. */
#define FRAMEOPTION_START_VALUE_FOLLOWING       0x01000 /* start is V. F. */
#define FRAMEOPTION_END_VALUE_FOLLOWING         0x02000 /* end is V. F. */

#define FRAMEOPTION_START_VALUE \
    (FRAMEOPTION_START_VALUE_PRECEDING | FRAMEOPTION_START_VALUE_FOLLOWING)
#define FRAMEOPTION_END_VALUE \
    (FRAMEOPTION_END_VALUE_PRECEDING | FRAMEOPTION_END_VALUE_FOLLOWING)

#define FRAMEOPTION_DEFAULTS \
    (FRAMEOPTION_RANGE | FRAMEOPTION_START_UNBOUNDED_PRECEDING | \
     FRAMEOPTION_END_CURRENT_ROW)

/*
 * RangeSubselect - subquery appearing in a FROM clause
 */
typedef struct RangeSubselect
{
    NodeTag     type;
    bool        lateral;        /* does it have LATERAL prefix? */
    Node       *subquery;       /* the untransformed sub-select clause */
    Alias      *alias;          /* table alias & optional column aliases */
} RangeSubselect;

/*
 * RangeFunction - function call appearing in a FROM clause
 */
typedef struct RangeFunction
{
    NodeTag     type;
    bool        lateral;        /* does it have LATERAL prefix? */
    Node       *funccallnode;   /* untransformed function call tree */
    Alias      *alias;          /* table alias & optional column aliases */
    List       *coldeflist;     /* list of ColumnDef nodes to describe result
                                 * of function returning RECORD */
} RangeFunction;

/*
 * ColumnDef - column definition (used in various creates)
 *
 * If the column has a default value, we may have the value expression
 * in either "raw" form (an untransformed parse tree) or "cooked" form
 * (a post-parse-analysis, executable expression tree), depending on
 * how this ColumnDef node was created (by parsing, or by inheritance
 * from an existing relation).  We should never have both in the same node!
 *
 * Similarly, we may have a COLLATE specification in either raw form
 * (represented as a CollateClause with arg==NULL) or cooked form
 * (the collation's OID).
 *
 * The constraints list may contain a CONSTR_DEFAULT item in a raw
 * parsetree produced by gram.y, but transformCreateStmt will remove
 * the item and set raw_default instead.  CONSTR_DEFAULT items
 * should not appear in any subsequent processing.
 */
typedef struct ColumnDef
{
    NodeTag     type;
    char       *colname;        /* name of column */
    TypeName   *typeName;       /* type of column */
    int         inhcount;       /* number of times column is inherited */
    bool        is_local;       /* column has local (non-inherited) def'n */
    bool        is_not_null;    /* NOT NULL constraint specified? */
    bool        is_from_type;   /* column definition came from table type */
    char        storage;        /* attstorage setting, or 0 for default */
    Node       *raw_default;    /* default value (untransformed parse tree) */
    Node       *cooked_default; /* default value (transformed expr tree) */
    CollateClause *collClause;  /* untransformed COLLATE spec, if any */
    Oid         collOid;        /* collation OID (InvalidOid if not set) */
    List       *constraints;    /* other constraints on column */
    List       *fdwoptions;     /* per-column FDW options */
} ColumnDef;

/*
 * TableLikeClause - CREATE TABLE ( ... LIKE ... ) clause
 */
typedef struct TableLikeClause
{
    NodeTag     type;
    RangeVar   *relation;
    bits32      options;        /* OR of TableLikeOption flags */
} TableLikeClause;

typedef enum TableLikeOption
{
    CREATE_TABLE_LIKE_DEFAULTS = 1 << 0,
    CREATE_TABLE_LIKE_CONSTRAINTS = 1 << 1,
    CREATE_TABLE_LIKE_INDEXES = 1 << 2,
    CREATE_TABLE_LIKE_STORAGE = 1 << 3,
    CREATE_TABLE_LIKE_COMMENTS = 1 << 4,
    CREATE_TABLE_LIKE_ALL = 0x7FFFFFFF
} TableLikeOption;

/*
 * IndexElem - index parameters (used in CREATE INDEX)
 *
 * For a plain index attribute, 'name' is the name of the table column to
 * index, and 'expr' is NULL.  For an index expression, 'name' is NULL and
 * 'expr' is the expression tree.
 */
typedef struct IndexElem
{
    NodeTag     type;
    char       *name;           /* name of attribute to index, or NULL */
    Node       *expr;           /* expression to index, or NULL */
    char       *indexcolname;   /* name for index column; NULL = default */
    List       *collation;      /* name of collation; NIL = default */
    List       *opclass;        /* name of desired opclass; NIL = default */
    SortByDir   ordering;       /* ASC/DESC/default */
    SortByNulls nulls_ordering; /* FIRST/LAST/default */
} IndexElem;

/*
 * DefElem - a generic "name = value" option definition
 *
 * In some contexts the name can be qualified.  Also, certain SQL commands
 * allow a SET/ADD/DROP action to be attached to option settings, so it's
 * convenient to carry a field for that too.  (Note: currently, it is our
 * practice that the grammar allows namespace and action only in statements
 * where they are relevant; C code can just ignore those fields in other
 * statements.)
 */
typedef enum DefElemAction
{
    DEFELEM_UNSPEC,             /* no action given */
    DEFELEM_SET,
    DEFELEM_ADD,
    DEFELEM_DROP
} DefElemAction;

typedef struct DefElem
{
    NodeTag     type;
    char       *defnamespace;   /* NULL if unqualified name */
    char       *defname;
    Node       *arg;            /* a (Value *) or a (TypeName *) */
    DefElemAction defaction;    /* unspecified action, or SET/ADD/DROP */
} DefElem;

/*
 * LockingClause - raw representation of FOR [NO KEY] UPDATE/[KEY] SHARE
 *      options
 *
 * Note: lockedRels == NIL means "all relations in query".  Otherwise it
 * is a list of RangeVar nodes.  (We use RangeVar mainly because it carries
 * a location field --- currently, parse analysis insists on unqualified
 * names in LockingClause.)
 */
typedef enum LockClauseStrength
{
    /* order is important -- see applyLockingClause */
    LCS_FORKEYSHARE,
    LCS_FORSHARE,
    LCS_FORNOKEYUPDATE,
    LCS_FORUPDATE
} LockClauseStrength;

typedef struct LockingClause
{
    NodeTag     type;
    List       *lockedRels;     /* FOR [KEY] UPDATE/SHARE relations */
    LockClauseStrength strength;
    bool        noWait;         /* NOWAIT option */
} LockingClause;

/*
 * XMLSERIALIZE (in raw parse tree only)
 */
typedef struct XmlSerialize
{
    NodeTag     type;
    XmlOptionType xmloption;    /* DOCUMENT or CONTENT */
    Node       *expr;
    TypeName   *typeName;
    int         location;       /* token location, or -1 if unknown */
} XmlSerialize;


/****************************************************************************
 *  Nodes for a Query tree
 ****************************************************************************/

/*--------------------
 * RangeTblEntry -
 *    A range table is a List of RangeTblEntry nodes.
 *
 *    A range table entry may represent a plain relation, a sub-select in
 *    FROM, or the result of a JOIN clause.  (Only explicit JOIN syntax
 *    produces an RTE, not the implicit join resulting from multiple FROM
 *    items.  This is because we only need the RTE to deal with SQL features
 *    like outer joins and join-output-column aliasing.)  Other special
 *    RTE types also exist, as indicated by RTEKind.
 *
 *    Note that we consider RTE_RELATION to cover anything that has a pg_class
 *    entry.  relkind distinguishes the sub-cases.
 *
 *    alias is an Alias node representing the AS alias-clause attached to the
 *    FROM expression, or NULL if no clause.
 *
 *    eref is the table reference name and column reference names (either
 *    real or aliases).  Note that system columns (OID etc) are not included
 *    in the column list.
 *    eref->aliasname is required to be present, and should generally be used
 *    to identify the RTE for error messages etc.
 *
 *    In RELATION RTEs, the colnames in both alias and eref are indexed by
 *    physical attribute number; this means there must be colname entries for
 *    dropped columns.  When building an RTE we insert empty strings ("") for
 *    dropped columns.  Note however that a stored rule may have nonempty
 *    colnames for columns dropped since the rule was created (and for that
 *    matter the colnames might be out of date due to column renamings).
 *    The same comments apply to FUNCTION RTEs when the function's return type
 *    is a named composite type.
 *
 *    In JOIN RTEs, the colnames in both alias and eref are one-to-one with
 *    joinaliasvars entries.  A JOIN RTE will omit columns of its inputs when
 *    those columns are known to be dropped at parse time.  Again, however,
 *    a stored rule might contain entries for columns dropped since the rule
 *    was created.  (This is only possible for columns not actually referenced
 *    in the rule.)  When loading a stored rule, we replace the joinaliasvars
 *    items for any such columns with NULL Consts.  (We can't simply delete
 *    them from the joinaliasvars list, because that would affect the attnums
 *    of Vars referencing the rest of the list.)
 *
 *    inh is TRUE for relation references that should be expanded to include
 *    inheritance children, if the rel has any.  This *must* be FALSE for
 *    RTEs other than RTE_RELATION entries.
 *
 *    inFromCl marks those range variables that are listed in the FROM clause.
 *    It's false for RTEs that are added to a query behind the scenes, such
 *    as the NEW and OLD variables for a rule, or the subqueries of a UNION.
 *    This flag is not used anymore during parsing, since the parser now uses
 *    a separate "namespace" data structure to control visibility, but it is
 *    needed by ruleutils.c to determine whether RTEs should be shown in
 *    decompiled queries.
 *
 *    requiredPerms and checkAsUser specify run-time access permissions
 *    checks to be performed at query startup.  The user must have *all*
 *    of the permissions that are OR'd together in requiredPerms (zero
 *    indicates no permissions checking).  If checkAsUser is not zero,
 *    then do the permissions checks using the access rights of that user,
 *    not the current effective user ID.  (This allows rules to act as
 *    setuid gateways.)  Permissions checks only apply to RELATION RTEs.
 *
 *    For SELECT/INSERT/UPDATE permissions, if the user doesn't have
 *    table-wide permissions then it is sufficient to have the permissions
 *    on all columns identified in selectedCols (for SELECT) and/or
 *    modifiedCols (for INSERT/UPDATE; we can tell which from the query type).
 *    selectedCols and modifiedCols are bitmapsets, which cannot have negative
 *    integer members, so we subtract FirstLowInvalidHeapAttributeNumber from
 *    column numbers before storing them in these fields.  A whole-row Var
 *    reference is represented by setting the bit for InvalidAttrNumber.
 *--------------------
 */
typedef enum RTEKind
{
    RTE_RELATION,               /* ordinary relation reference */
    RTE_SUBQUERY,               /* subquery in FROM */
    RTE_JOIN,                   /* join */
    RTE_FUNCTION,               /* function in FROM */
    RTE_VALUES,                 /* VALUES (<exprlist>), (<exprlist>), ... */
    RTE_CTE                     /* common table expr (WITH list element) */
} RTEKind;

typedef struct RangeTblEntry
{
    NodeTag     type;

    RTEKind     rtekind;        /* see above */

    /*
     * XXX the fields applicable to only some rte kinds should be merged into
     * a union.  I didn't do this yet because the diffs would impact a lot of
     * code that is being actively worked on.  FIXME someday.
     */

    /*
     * Fields valid for a plain relation RTE (else zero):
     */
    Oid         relid;          /* OID of the relation */
    char        relkind;        /* relation kind (see pg_class.relkind) */

    /*
     * Fields valid for a subquery RTE (else NULL):
     */
    Query      *subquery;       /* the sub-query */
    bool        security_barrier;       /* is from security_barrier view? */

    /*
     * Fields valid for a join RTE (else NULL/zero):
     *
     * joinaliasvars is a list of Vars or COALESCE expressions corresponding
     * to the columns of the join result.  An alias Var referencing column K
     * of the join result can be replaced by the K'th element of joinaliasvars
     * --- but to simplify the task of reverse-listing aliases correctly, we
     * do not do that until planning time.  In a Query loaded from a stored
     * rule, it is also possible for joinaliasvars items to be NULL Consts,
     * denoting columns dropped since the rule was made.
     */
    JoinType    jointype;       /* type of join */
    List       *joinaliasvars;  /* list of alias-var expansions */

    /*
     * Fields valid for a function RTE (else NULL):
     *
     * If the function returns RECORD, funccoltypes lists the column types
     * declared in the RTE's column type specification, funccoltypmods lists
     * their declared typmods, funccolcollations their collations.  Otherwise,
     * those fields are NIL.
     */
    Node       *funcexpr;       /* expression tree for func call */
    List       *funccoltypes;   /* OID list of column type OIDs */
    List       *funccoltypmods; /* integer list of column typmods */
    List       *funccolcollations;      /* OID list of column collation OIDs */

    /*
     * Fields valid for a values RTE (else NIL):
     */
    List       *values_lists;   /* list of expression lists */
    List       *values_collations;      /* OID list of column collation OIDs */

    /*
     * Fields valid for a CTE RTE (else NULL/zero):
     */
    char       *ctename;        /* name of the WITH list item */
    Index       ctelevelsup;    /* number of query levels up */
    bool        self_reference; /* is this a recursive self-reference? */
    List       *ctecoltypes;    /* OID list of column type OIDs */
    List       *ctecoltypmods;  /* integer list of column typmods */
    List       *ctecolcollations;       /* OID list of column collation OIDs */

    /*
     * Fields valid in all RTEs:
     */
    Alias      *alias;          /* user-written alias clause, if any */
    Alias      *eref;           /* expanded reference names */
    bool        lateral;        /* subquery, function, or values is LATERAL? */
    bool        inh;            /* inheritance requested? */
    bool        inFromCl;       /* present in FROM clause? */
    AclMode     requiredPerms;  /* bitmask of required access permissions */
    Oid         checkAsUser;    /* if valid, check access as this role */
    Bitmapset  *selectedCols;   /* columns needing SELECT permission */
    Bitmapset  *modifiedCols;   /* columns needing INSERT/UPDATE permission */
} RangeTblEntry;

/*
 * SortGroupClause -
 *      representation of ORDER BY, GROUP BY, PARTITION BY,
 *      DISTINCT, DISTINCT ON items
 *
 * You might think that ORDER BY is only interested in defining ordering,
 * and GROUP/DISTINCT are only interested in defining equality.  However,
 * one way to implement grouping is to sort and then apply a "uniq"-like
 * filter.  So it's also interesting to keep track of possible sort operators
 * for GROUP/DISTINCT, and in particular to try to sort for the grouping
 * in a way that will also yield a requested ORDER BY ordering.  So we need
 * to be able to compare ORDER BY and GROUP/DISTINCT lists, which motivates
 * the decision to give them the same representation.
 *
 * tleSortGroupRef must match ressortgroupref of exactly one entry of the
 *      query's targetlist; that is the expression to be sorted or grouped by.
 * eqop is the OID of the equality operator.
 * sortop is the OID of the ordering operator (a "<" or ">" operator),
 *      or InvalidOid if not available.
 * nulls_first means about what you'd expect.  If sortop is InvalidOid
 *      then nulls_first is meaningless and should be set to false.
 * hashable is TRUE if eqop is hashable (note this condition also depends
 *      on the datatype of the input expression).
 *
 * In an ORDER BY item, all fields must be valid.  (The eqop isn't essential
 * here, but it's cheap to get it along with the sortop, and requiring it
 * to be valid eases comparisons to grouping items.)  Note that this isn't
 * actually enough information to determine an ordering: if the sortop is
 * collation-sensitive, a collation OID is needed too.  We don't store the
 * collation in SortGroupClause because it's not available at the time the
 * parser builds the SortGroupClause; instead, consult the exposed collation
 * of the referenced targetlist expression to find out what it is.
 *
 * In a grouping item, eqop must be valid.  If the eqop is a btree equality
 * operator, then sortop should be set to a compatible ordering operator.
 * We prefer to set eqop/sortop/nulls_first to match any ORDER BY item that
 * the query presents for the same tlist item.  If there is none, we just
 * use the default ordering op for the datatype.
 *
 * If the tlist item's type has a hash opclass but no btree opclass, then
 * we will set eqop to the hash equality operator, sortop to InvalidOid,
 * and nulls_first to false.  A grouping item of this kind can only be
 * implemented by hashing, and of course it'll never match an ORDER BY item.
 *
 * The hashable flag is provided since we generally have the requisite
 * information readily available when the SortGroupClause is constructed,
 * and it's relatively expensive to get it again later.  Note there is no
 * need for a "sortable" flag since OidIsValid(sortop) serves the purpose.
 *
 * A query might have both ORDER BY and DISTINCT (or DISTINCT ON) clauses.
 * In SELECT DISTINCT, the distinctClause list is as long or longer than the
 * sortClause list, while in SELECT DISTINCT ON it's typically shorter.
 * The two lists must match up to the end of the shorter one --- the parser
 * rearranges the distinctClause if necessary to make this true.  (This
 * restriction ensures that only one sort step is needed to both satisfy the
 * ORDER BY and set up for the Unique step.  This is semantically necessary
 * for DISTINCT ON, and presents no real drawback for DISTINCT.)
 */
typedef struct SortGroupClause
{
    NodeTag     type;
    Index       tleSortGroupRef;    /* reference into targetlist */
    Oid         eqop;           /* the equality operator ('=' op) */
    Oid         sortop;         /* the ordering operator ('<' op), or 0 */
    bool        nulls_first;    /* do NULLs come before normal values? */
    bool        hashable;       /* can eqop be implemented by hashing? */
} SortGroupClause;

/*
 * WindowClause -
 *      transformed representation of WINDOW and OVER clauses
 *
 * A parsed Query's windowClause list contains these structs.  "name" is set
 * if the clause originally came from WINDOW, and is NULL if it originally
 * was an OVER clause (but note that we collapse out duplicate OVERs).
 * partitionClause and orderClause are lists of SortGroupClause structs.
 * winref is an ID number referenced by WindowFunc nodes; it must be unique
 * among the members of a Query's windowClause list.
 * When refname isn't null, the partitionClause is always copied from there;
 * the orderClause might or might not be copied (see copiedOrder); the framing
 * options are never copied, per spec.
 */
typedef struct WindowClause
{
    NodeTag     type;
    char       *name;           /* window name (NULL in an OVER clause) */
    char       *refname;        /* referenced window name, if any */
    List       *partitionClause;    /* PARTITION BY list */
    List       *orderClause;    /* ORDER BY list */
    int         frameOptions;   /* frame_clause options, see WindowDef */
    Node       *startOffset;    /* expression for starting bound, if any */
    Node       *endOffset;      /* expression for ending bound, if any */
    Index       winref;         /* ID referenced by window functions */
    bool        copiedOrder;    /* did we copy orderClause from refname? */
} WindowClause;

/*
 * RowMarkClause -
 *     parser output representation of FOR [KEY] UPDATE/SHARE clauses
 *
 * Query.rowMarks contains a separate RowMarkClause node for each relation
 * identified as a FOR [KEY] UPDATE/SHARE target.  If one of these clauses
 * is applied to a subquery, we generate RowMarkClauses for all normal and
 * subquery rels in the subquery, but they are marked pushedDown = true to
 * distinguish them from clauses that were explicitly written at this query
 * level.  Also, Query.hasForUpdate tells whether there were explicit FOR
 * UPDATE/SHARE/KEY SHARE clauses in the current query level.
 */
typedef struct RowMarkClause
{
    NodeTag     type;
    Index       rti;            /* range table index of target relation */
    LockClauseStrength strength;
    bool        noWait;         /* NOWAIT option */
    bool        pushedDown;     /* pushed down from higher query level? */
} RowMarkClause;

/*
 * WithClause -
 *     representation of WITH clause
 *
 * Note: WithClause does not propagate into the Query representation;
 * but CommonTableExpr does.
 */
typedef struct WithClause
{
    NodeTag     type;
    List       *ctes;           /* list of CommonTableExprs */
    bool        recursive;      /* true = WITH RECURSIVE */
    int         location;       /* token location, or -1 if unknown */
} WithClause;

/*
 * CommonTableExpr -
 *     representation of WITH list element
 *
 * We don't currently support the SEARCH or CYCLE clause.
 */
typedef struct CommonTableExpr
{
    NodeTag     type;
    char       *ctename;        /* query name (never qualified) */
    List       *aliascolnames;  /* optional list of column names */
    /* SelectStmt/InsertStmt/etc before parse analysis, Query afterwards: */
    Node       *ctequery;       /* the CTE's subquery */
    int         location;       /* token location, or -1 if unknown */
    /* These fields are set during parse analysis: */
    bool        cterecursive;   /* is this CTE actually recursive? */
    int         cterefcount;    /* number of RTEs referencing this CTE
                                 * (excluding internal self-references) */
    List       *ctecolnames;    /* list of output column names */
    List       *ctecoltypes;    /* OID list of output column type OIDs */
    List       *ctecoltypmods;  /* integer list of output column typmods */
    List       *ctecolcollations;       /* OID list of column collation OIDs */
} CommonTableExpr;

/* Convenience macro to get the output tlist of a CTE's query */
#define GetCTETargetList(cte) \
    (AssertMacro(IsA((cte)->ctequery, Query)), \
     ((Query *) (cte)->ctequery)->commandType == CMD_SELECT ? \
     ((Query *) (cte)->ctequery)->targetList : \
     ((Query *) (cte)->ctequery)->returningList)


/*****************************************************************************
 *      Optimizable Statements
 *****************************************************************************/

/* ----------------------
 *      Insert Statement
 *
 * The source expression is represented by SelectStmt for both the
 * SELECT and VALUES cases.  If selectStmt is NULL, then the query
 * is INSERT ... DEFAULT VALUES.
 * ----------------------
 */
typedef struct InsertStmt
{
    NodeTag     type;
    RangeVar   *relation;       /* relation to insert into */
    List       *cols;           /* optional: names of the target columns */
    Node       *selectStmt;     /* the source SELECT/VALUES, or NULL */
    List       *returningList;  /* list of expressions to return */
    WithClause *withClause;     /* WITH clause */
} InsertStmt;

/* ----------------------
 *      Delete Statement
 * ----------------------
 */
typedef struct DeleteStmt
{
    NodeTag     type;
    RangeVar   *relation;       /* relation to delete from */
    List       *usingClause;    /* optional using clause for more tables */
    Node       *whereClause;    /* qualifications */
    List       *returningList;  /* list of expressions to return */
    WithClause *withClause;     /* WITH clause */
} DeleteStmt;

/* ----------------------
 *      Update Statement
 * ----------------------
 */
typedef struct UpdateStmt
{
    NodeTag     type;
    RangeVar   *relation;       /* relation to update */
    List       *targetList;     /* the target list (of ResTarget) */
    Node       *whereClause;    /* qualifications */
    List       *fromClause;     /* optional from clause for more tables */
    List       *returningList;  /* list of expressions to return */
    WithClause *withClause;     /* WITH clause */
} UpdateStmt;

/* ----------------------
 *      Select Statement
 *
 * A "simple" SELECT is represented in the output of gram.y by a single
 * SelectStmt node; so is a VALUES construct.  A query containing set
 * operators (UNION, INTERSECT, EXCEPT) is represented by a tree of SelectStmt
 * nodes, in which the leaf nodes are component SELECTs and the internal nodes
 * represent UNION, INTERSECT, or EXCEPT operators.  Using the same node
 * type for both leaf and internal nodes allows gram.y to stick ORDER BY,
 * LIMIT, etc, clause values into a SELECT statement without worrying
 * whether it is a simple or compound SELECT.
 * ----------------------
 */
typedef enum SetOperation
{
    SETOP_NONE = 0,
    SETOP_UNION,
    SETOP_INTERSECT,
    SETOP_EXCEPT
} SetOperation;

typedef struct SelectStmt
{
    NodeTag     type;

    /*
     * These fields are used only in "leaf" SelectStmts.
     */
    List       *distinctClause; /* NULL, list of DISTINCT ON exprs, or
                                 * lcons(NIL,NIL) for all (SELECT DISTINCT) */
    IntoClause *intoClause;     /* target for SELECT INTO */
    List       *targetList;     /* the target list (of ResTarget) */
    List       *fromClause;     /* the FROM clause */
    Node       *whereClause;    /* WHERE qualification */
    List       *groupClause;    /* GROUP BY clauses */
    Node       *havingClause;   /* HAVING conditional-expression */
    List       *windowClause;   /* WINDOW window_name AS (...), ... */

    /*
     * In a "leaf" node representing a VALUES list, the above fields are all
     * null, and instead this field is set.  Note that the elements of the
     * sublists are just expressions, without ResTarget decoration. Also note
     * that a list element can be DEFAULT (represented as a SetToDefault
     * node), regardless of the context of the VALUES list. It's up to parse
     * analysis to reject that where not valid.
     */
    List       *valuesLists;    /* untransformed list of expression lists */

    /*
     * These fields are used in both "leaf" SelectStmts and upper-level
     * SelectStmts.
     */
    List       *sortClause;     /* sort clause (a list of SortBy's) */
    Node       *limitOffset;    /* # of result tuples to skip */
    Node       *limitCount;     /* # of result tuples to return */
    List       *lockingClause;  /* FOR UPDATE (list of LockingClause's) */
    WithClause *withClause;     /* WITH clause */

    /*
     * These fields are used only in upper-level SelectStmts.
     */
    SetOperation op;            /* type of set op */
    bool        all;            /* ALL specified? */
    struct SelectStmt *larg;    /* left child */
    struct SelectStmt *rarg;    /* right child */
    /* Eventually add fields for CORRESPONDING spec here */
} SelectStmt;


/* ----------------------
 *      Set Operation node for post-analysis query trees
 *
 * After parse analysis, a SELECT with set operations is represented by a
 * top-level Query node containing the leaf SELECTs as subqueries in its
 * range table.  Its setOperations field shows the tree of set operations,
 * with leaf SelectStmt nodes replaced by RangeTblRef nodes, and internal
 * nodes replaced by SetOperationStmt nodes.  Information about the output
 * column types is added, too.  (Note that the child nodes do not necessarily
 * produce these types directly, but we've checked that their output types
 * can be coerced to the output column type.)  Also, if it's not UNION ALL,
 * information about the types' sort/group semantics is provided in the form
 * of a SortGroupClause list (same representation as, eg, DISTINCT).
 * The resolved common column collations are provided too; but note that if
 * it's not UNION ALL, it's okay for a column to not have a common collation,
 * so a member of the colCollations list could be InvalidOid even though the
 * column has a collatable type.
 * ----------------------
 */
typedef struct SetOperationStmt
{
    NodeTag     type;
    SetOperation op;            /* type of set op */
    bool        all;            /* ALL specified? */
    Node       *larg;           /* left child */
    Node       *rarg;           /* right child */
    /* Eventually add fields for CORRESPONDING spec here */

    /* Fields derived during parse analysis: */
    List       *colTypes;       /* OID list of output column type OIDs */
    List       *colTypmods;     /* integer list of output column typmods */
    List       *colCollations;  /* OID list of output column collation OIDs */
    List       *groupClauses;   /* a list of SortGroupClause's */
    /* groupClauses is NIL if UNION ALL, but must be set otherwise */
} SetOperationStmt;


/*****************************************************************************
 *      Other Statements (no optimizations required)
 *
 *      These are not touched by parser/analyze.c except to put them into
 *      the utilityStmt field of a Query.  This is eventually passed to
 *      ProcessUtility (by-passing rewriting and planning).  Some of the
 *      statements do need attention from parse analysis, and this is
 *      done by routines in parser/parse_utilcmd.c after ProcessUtility
 *      receives the command for execution.
 *****************************************************************************/

/*
 * When a command can act on several kinds of objects with only one
 * parse structure required, use these constants to designate the
 * object type.  Note that commands typically don't support all the types.
 */

typedef enum ObjectType
{
    OBJECT_AGGREGATE,
    OBJECT_ATTRIBUTE,           /* type's attribute, when distinct from column */
    OBJECT_CAST,
    OBJECT_COLUMN,
    OBJECT_CONSTRAINT,
    OBJECT_COLLATION,
    OBJECT_CONVERSION,
    OBJECT_DATABASE,
    OBJECT_DOMAIN,
    OBJECT_EVENT_TRIGGER,
    OBJECT_EXTENSION,
    OBJECT_FDW,
    OBJECT_FOREIGN_SERVER,
    OBJECT_FOREIGN_TABLE,
    OBJECT_FUNCTION,
    OBJECT_INDEX,
    OBJECT_LANGUAGE,
    OBJECT_LARGEOBJECT,
    OBJECT_MATVIEW,
    OBJECT_OPCLASS,
    OBJECT_OPERATOR,
    OBJECT_OPFAMILY,
    OBJECT_ROLE,
    OBJECT_RULE,
    OBJECT_SCHEMA,
    OBJECT_SEQUENCE,
    OBJECT_TABLE,
    OBJECT_TABLESPACE,
    OBJECT_TRIGGER,
    OBJECT_TSCONFIGURATION,
    OBJECT_TSDICTIONARY,
    OBJECT_TSPARSER,
    OBJECT_TSTEMPLATE,
    OBJECT_TYPE,
    OBJECT_VIEW
} ObjectType;

/* ----------------------
 *      Create Schema Statement
 *
 * NOTE: the schemaElts list contains raw parsetrees for component statements
 * of the schema, such as CREATE TABLE, GRANT, etc.  These are analyzed and
 * executed after the schema itself is created.
 * ----------------------
 */
typedef struct CreateSchemaStmt
{
    NodeTag     type;
    char       *schemaname;     /* the name of the schema to create */
    char       *authid;         /* the owner of the created schema */
    List       *schemaElts;     /* schema components (list of parsenodes) */
    bool        if_not_exists;  /* just do nothing if schema already exists? */
} CreateSchemaStmt;

typedef enum DropBehavior
{
    DROP_RESTRICT,              /* drop fails if any dependent objects */
    DROP_CASCADE                /* remove dependent objects too */
} DropBehavior;

/* ----------------------
 *  Alter Table
 * ----------------------
 */
typedef struct AlterTableStmt
{
    NodeTag     type;
    RangeVar   *relation;       /* table to work on */
    List       *cmds;           /* list of subcommands */
    ObjectType  relkind;        /* type of object */
    bool        missing_ok;     /* skip error if table missing */
} AlterTableStmt;

typedef enum AlterTableType
{
    AT_AddColumn,               /* add column */
    AT_AddColumnRecurse,        /* internal to commands/tablecmds.c */
    AT_AddColumnToView,         /* implicitly via CREATE OR REPLACE VIEW */
    AT_ColumnDefault,           /* alter column default */
    AT_DropNotNull,             /* alter column drop not null */
    AT_SetNotNull,              /* alter column set not null */
    AT_SetStatistics,           /* alter column set statistics */
    AT_SetOptions,              /* alter column set ( options ) */
    AT_ResetOptions,            /* alter column reset ( options ) */
    AT_SetStorage,              /* alter column set storage */
    AT_DropColumn,              /* drop column */
    AT_DropColumnRecurse,       /* internal to commands/tablecmds.c */
    AT_AddIndex,                /* add index */
    AT_ReAddIndex,              /* internal to commands/tablecmds.c */
    AT_AddConstraint,           /* add constraint */
    AT_AddConstraintRecurse,    /* internal to commands/tablecmds.c */
    AT_ReAddConstraint,         /* internal to commands/tablecmds.c */
    AT_ValidateConstraint,      /* validate constraint */
    AT_ValidateConstraintRecurse,       /* internal to commands/tablecmds.c */
    AT_ProcessedConstraint,     /* pre-processed add constraint (local in
                                 * parser/parse_utilcmd.c) */
    AT_AddIndexConstraint,      /* add constraint using existing index */
    AT_DropConstraint,          /* drop constraint */
    AT_DropConstraintRecurse,   /* internal to commands/tablecmds.c */
    AT_AlterColumnType,         /* alter column type */
    AT_AlterColumnGenericOptions,       /* alter column OPTIONS (...) */
    AT_ChangeOwner,             /* change owner */
    AT_ClusterOn,               /* CLUSTER ON */
    AT_DropCluster,             /* SET WITHOUT CLUSTER */
    AT_AddOids,                 /* SET WITH OIDS */
    AT_AddOidsRecurse,          /* internal to commands/tablecmds.c */
    AT_DropOids,                /* SET WITHOUT OIDS */
    AT_SetTableSpace,           /* SET TABLESPACE */
    AT_SetRelOptions,           /* SET (...) -- AM specific parameters */
    AT_ResetRelOptions,         /* RESET (...) -- AM specific parameters */
    AT_ReplaceRelOptions,       /* replace reloption list in its entirety */
    AT_EnableTrig,              /* ENABLE TRIGGER name */
    AT_EnableAlwaysTrig,        /* ENABLE ALWAYS TRIGGER name */
    AT_EnableReplicaTrig,       /* ENABLE REPLICA TRIGGER name */
    AT_DisableTrig,             /* DISABLE TRIGGER name */
    AT_EnableTrigAll,           /* ENABLE TRIGGER ALL */
    AT_DisableTrigAll,          /* DISABLE TRIGGER ALL */
    AT_EnableTrigUser,          /* ENABLE TRIGGER USER */
    AT_DisableTrigUser,         /* DISABLE TRIGGER USER */
    AT_EnableRule,              /* ENABLE RULE name */
    AT_EnableAlwaysRule,        /* ENABLE ALWAYS RULE name */
    AT_EnableReplicaRule,       /* ENABLE REPLICA RULE name */
    AT_DisableRule,             /* DISABLE RULE name */
    AT_AddInherit,              /* INHERIT parent */
    AT_DropInherit,             /* NO INHERIT parent */
    AT_AddOf,                   /* OF <type_name> */
    AT_DropOf,                  /* NOT OF */
    AT_GenericOptions           /* OPTIONS (...) */
} AlterTableType;

typedef struct AlterTableCmd    /* one subcommand of an ALTER TABLE */
{
    NodeTag     type;
    AlterTableType subtype;     /* Type of table alteration to apply */
    char       *name;           /* column, constraint, or trigger to act on,
                                 * or new owner or tablespace */
    Node       *def;            /* definition of new column, index,
                                 * constraint, or parent table */
    DropBehavior behavior;      /* RESTRICT or CASCADE for DROP cases */
    bool        missing_ok;     /* skip error if missing? */
} AlterTableCmd;


/* ----------------------
 *  Alter Domain
 *
 * The fields are used in different ways by the different variants of
 * this command.
 * ----------------------
 */
typedef struct AlterDomainStmt
{
    NodeTag     type;
    char        subtype;        /*------------
                                 *  T = alter column default
                                 *  N = alter column drop not null
                                 *  O = alter column set not null
                                 *  C = add constraint
                                 *  X = drop constraint
                                 *------------
                                 */
    List       *typeName;       /* domain to work on */
    char       *name;           /* column or constraint name to act on */
    Node       *def;            /* definition of default or constraint */
    DropBehavior behavior;      /* RESTRICT or CASCADE for DROP cases */
    bool        missing_ok;     /* skip error if missing? */
} AlterDomainStmt;


/* ----------------------
 *      Grant|Revoke Statement
 * ----------------------
 */
typedef enum GrantTargetType
{
    ACL_TARGET_OBJECT,          /* grant on specific named object(s) */
    ACL_TARGET_ALL_IN_SCHEMA,   /* grant on all objects in given schema(s) */
    ACL_TARGET_DEFAULTS         /* ALTER DEFAULT PRIVILEGES */
} GrantTargetType;

typedef enum GrantObjectType
{
    ACL_OBJECT_COLUMN,          /* column */
    ACL_OBJECT_RELATION,        /* table, view */
    ACL_OBJECT_SEQUENCE,        /* sequence */
    ACL_OBJECT_DATABASE,        /* database */
    ACL_OBJECT_DOMAIN,          /* domain */
    ACL_OBJECT_FDW,             /* foreign-data wrapper */
    ACL_OBJECT_FOREIGN_SERVER,  /* foreign server */
    ACL_OBJECT_FUNCTION,        /* function */
    ACL_OBJECT_LANGUAGE,        /* procedural language */
    ACL_OBJECT_LARGEOBJECT,     /* largeobject */
    ACL_OBJECT_NAMESPACE,       /* namespace */
    ACL_OBJECT_TABLESPACE,      /* tablespace */
    ACL_OBJECT_TYPE             /* type */
} GrantObjectType;

typedef struct GrantStmt
{
    NodeTag     type;
    bool        is_grant;       /* true = GRANT, false = REVOKE */
    GrantTargetType targtype;   /* type of the grant target */
    GrantObjectType objtype;    /* kind of object being operated on */
    List       *objects;        /* list of RangeVar nodes, FuncWithArgs nodes,
                                 * or plain names (as Value strings) */
    List       *privileges;     /* list of AccessPriv nodes */
    /* privileges == NIL denotes ALL PRIVILEGES */
    List       *grantees;       /* list of PrivGrantee nodes */
    bool        grant_option;   /* grant or revoke grant option */
    DropBehavior behavior;      /* drop behavior (for REVOKE) */
} GrantStmt;

typedef struct PrivGrantee
{
    NodeTag     type;
    char       *rolname;        /* if NULL then PUBLIC */
} PrivGrantee;

/*
 * Note: FuncWithArgs carries only the types of the input parameters of the
 * function.  So it is sufficient to identify an existing function, but it
 * is not enough info to define a function nor to call it.
 */
typedef struct FuncWithArgs
{
    NodeTag     type;
    List       *funcname;       /* qualified name of function */
    List       *funcargs;       /* list of Typename nodes */
} FuncWithArgs;

/*
 * An access privilege, with optional list of column names
 * priv_name == NULL denotes ALL PRIVILEGES (only used with a column list)
 * cols == NIL denotes "all columns"
 * Note that simple "ALL PRIVILEGES" is represented as a NIL list, not
 * an AccessPriv with both fields null.
 */
typedef struct AccessPriv
{
    NodeTag     type;
    char       *priv_name;      /* string name of privilege */
    List       *cols;           /* list of Value strings */
} AccessPriv;

/* ----------------------
 *      Grant/Revoke Role Statement
 *
 * Note: because of the parsing ambiguity with the GRANT <privileges>
 * statement, granted_roles is a list of AccessPriv; the execution code
 * should complain if any column lists appear.  grantee_roles is a list
 * of role names, as Value strings.
 * ----------------------
 */
typedef struct GrantRoleStmt
{
    NodeTag     type;
    List       *granted_roles;  /* list of roles to be granted/revoked */
    List       *grantee_roles;  /* list of member roles to add/delete */
    bool        is_grant;       /* true = GRANT, false = REVOKE */
    bool        admin_opt;      /* with admin option */
    char       *grantor;        /* set grantor to other than current role */
    DropBehavior behavior;      /* drop behavior (for REVOKE) */
} GrantRoleStmt;

/* ----------------------
 *  Alter Default Privileges Statement
 * ----------------------
 */
typedef struct AlterDefaultPrivilegesStmt
{
    NodeTag     type;
    List       *options;        /* list of DefElem */
    GrantStmt  *action;         /* GRANT/REVOKE action (with objects=NIL) */
} AlterDefaultPrivilegesStmt;

/* ----------------------
 *      Copy Statement
 *
 * We support "COPY relation FROM file", "COPY relation TO file", and
 * "COPY (query) TO file".  In any given CopyStmt, exactly one of "relation"
 * and "query" must be non-NULL.
 * ----------------------
 */
typedef struct CopyStmt
{
    NodeTag     type;
    RangeVar   *relation;       /* the relation to copy */
    Node       *query;          /* the SELECT query to copy */
    List       *attlist;        /* List of column names (as Strings), or NIL
                                 * for all columns */
    bool        is_from;        /* TO or FROM */
    bool        is_program;     /* is 'filename' a program to popen? */
    char       *filename;       /* filename, or NULL for STDIN/STDOUT */
    List       *options;        /* List of DefElem nodes */
} CopyStmt;

/* ----------------------
 * SET Statement (includes RESET)
 *
 * "SET var TO DEFAULT" and "RESET var" are semantically equivalent, but we
 * preserve the distinction in VariableSetKind for CreateCommandTag().
 * ----------------------
 */
typedef enum
{
    VAR_SET_VALUE,              /* SET var = value */
    VAR_SET_DEFAULT,            /* SET var TO DEFAULT */
    VAR_SET_CURRENT,            /* SET var FROM CURRENT */
    VAR_SET_MULTI,              /* special case for SET TRANSACTION ... */
    VAR_RESET,                  /* RESET var */
    VAR_RESET_ALL               /* RESET ALL */
} VariableSetKind;

typedef struct VariableSetStmt
{
    NodeTag     type;
    VariableSetKind kind;
    char       *name;           /* variable to be set */
    List       *args;           /* List of A_Const nodes */
    bool        is_local;       /* SET LOCAL? */
} VariableSetStmt;

/* ----------------------
 * Show Statement
 * ----------------------
 */
typedef struct VariableShowStmt
{
    NodeTag     type;
    char       *name;
} VariableShowStmt;

/* ----------------------
 *      Create Table Statement
 *
 * NOTE: in the raw gram.y output, ColumnDef and Constraint nodes are
 * intermixed in tableElts, and constraints is NIL.  After parse analysis,
 * tableElts contains just ColumnDefs, and constraints contains just
 * Constraint nodes (in fact, only CONSTR_CHECK nodes, in the present
 * implementation).
 * ----------------------
 */

typedef struct CreateStmt
{
    NodeTag     type;
    RangeVar   *relation;       /* relation to create */
    List       *tableElts;      /* column definitions (list of ColumnDef) */
    List       *inhRelations;   /* relations to inherit from (list of
                                 * inhRelation) */
    TypeName   *ofTypename;     /* OF typename */
    List       *constraints;    /* constraints (list of Constraint nodes) */
    List       *options;        /* options from WITH clause */
    OnCommitAction oncommit;    /* what do we do at COMMIT? */
    char       *tablespacename; /* table space to use, or NULL */
    bool        if_not_exists;  /* just do nothing if it already exists? */
} CreateStmt;

/* ----------
 * Definitions for constraints in CreateStmt
 *
 * Note that column defaults are treated as a type of constraint,
 * even though that's a bit odd semantically.
 *
 * For constraints that use expressions (CONSTR_CHECK, CONSTR_DEFAULT)
 * we may have the expression in either "raw" form (an untransformed
 * parse tree) or "cooked" form (the nodeToString representation of
 * an executable expression tree), depending on how this Constraint
 * node was created (by parsing, or by inheritance from an existing
 * relation).  We should never have both in the same node!
 *
 * FKCONSTR_ACTION_xxx values are stored into pg_constraint.confupdtype
 * and pg_constraint.confdeltype columns; FKCONSTR_MATCH_xxx values are
 * stored into pg_constraint.confmatchtype.  Changing the code values may
 * require an initdb!
 *
 * If skip_validation is true then we skip checking that the existing rows
 * in the table satisfy the constraint, and just install the catalog entries
 * for the constraint.  A new FK constraint is marked as valid iff
 * initially_valid is true.  (Usually skip_validation and initially_valid
 * are inverses, but we can set both true if the table is known empty.)
 *
 * Constraint attributes (DEFERRABLE etc) are initially represented as
 * separate Constraint nodes for simplicity of parsing.  parse_utilcmd.c makes
 * a pass through the constraints list to insert the info into the appropriate
 * Constraint node.
 * ----------
 */

typedef enum ConstrType         /* types of constraints */
{
    CONSTR_NULL,                /* not standard SQL, but a lot of people expect it */
    CONSTR_NOTNULL,
    CONSTR_DEFAULT,
    CONSTR_CHECK,
    CONSTR_PRIMARY,
    CONSTR_UNIQUE,
    CONSTR_EXCLUSION,
    CONSTR_FOREIGN,
    CONSTR_ATTR_DEFERRABLE,     /* attributes for previous constraint node */
    CONSTR_ATTR_NOT_DEFERRABLE,
    CONSTR_ATTR_DEFERRED,
    CONSTR_ATTR_IMMEDIATE
} ConstrType;

/* Foreign key action codes */
#define FKCONSTR_ACTION_NOACTION    'a'
#define FKCONSTR_ACTION_RESTRICT    'r'
#define FKCONSTR_ACTION_CASCADE     'c'
#define FKCONSTR_ACTION_SETNULL     'n'
#define FKCONSTR_ACTION_SETDEFAULT  'd'

/* Foreign key matchtype codes */
#define FKCONSTR_MATCH_FULL         'f'
#define FKCONSTR_MATCH_PARTIAL      'p'
#define FKCONSTR_MATCH_SIMPLE       's'

typedef struct Constraint
{
    NodeTag     type;
    ConstrType  contype;        /* see above */

    /* Fields used for most/all constraint types: */
    char       *conname;        /* Constraint name, or NULL if unnamed */
    bool        deferrable;     /* DEFERRABLE? */
    bool        initdeferred;   /* INITIALLY DEFERRED? */
    int         location;       /* token location, or -1 if unknown */

    /* Fields used for constraints with expressions (CHECK and DEFAULT): */
    bool        is_no_inherit;  /* is constraint non-inheritable? */
    Node       *raw_expr;       /* expr, as untransformed parse tree */
    char       *cooked_expr;    /* expr, as nodeToString representation */

    /* Fields used for unique constraints (UNIQUE and PRIMARY KEY): */
    List       *keys;           /* String nodes naming referenced column(s) */

    /* Fields used for EXCLUSION constraints: */
    List       *exclusions;     /* list of (IndexElem, operator name) pairs */

    /* Fields used for index constraints (UNIQUE, PRIMARY KEY, EXCLUSION): */
    List       *options;        /* options from WITH clause */
    char       *indexname;      /* existing index to use; otherwise NULL */
    char       *indexspace;     /* index tablespace; NULL for default */
    /* These could be, but currently are not, used for UNIQUE/PKEY: */
    char       *access_method;  /* index access method; NULL for default */
    Node       *where_clause;   /* partial index predicate */

    /* Fields used for FOREIGN KEY constraints: */
    RangeVar   *pktable;        /* Primary key table */
    List       *fk_attrs;       /* Attributes of foreign key */
    List       *pk_attrs;       /* Corresponding attrs in PK table */
    char        fk_matchtype;   /* FULL, PARTIAL, SIMPLE */
    char        fk_upd_action;  /* ON UPDATE action */
    char        fk_del_action;  /* ON DELETE action */
    List       *old_conpfeqop;  /* pg_constraint.conpfeqop of my former self */

    /* Fields used for constraints that allow a NOT VALID specification */
    bool        skip_validation;    /* skip validation of existing rows? */
    bool        initially_valid;    /* mark the new constraint as valid? */
} Constraint;

/* ----------------------
 *      Create/Drop Table Space Statements
 * ----------------------
 */

typedef struct CreateTableSpaceStmt
{
    NodeTag     type;
    char       *tablespacename;
    char       *owner;
    char       *location;
} CreateTableSpaceStmt;

typedef struct DropTableSpaceStmt
{
    NodeTag     type;
    char       *tablespacename;
    bool        missing_ok;     /* skip error if missing? */
} DropTableSpaceStmt;

typedef struct AlterTableSpaceOptionsStmt
{
    NodeTag     type;
    char       *tablespacename;
    List       *options;
    bool        isReset;
} AlterTableSpaceOptionsStmt;

/* ----------------------
 *      Create/Alter Extension Statements
 * ----------------------
 */

typedef struct CreateExtensionStmt
{
    NodeTag     type;
    char       *extname;
    bool        if_not_exists;  /* just do nothing if it already exists? */
    List       *options;        /* List of DefElem nodes */
} CreateExtensionStmt;

/* Only used for ALTER EXTENSION UPDATE; later might need an action field */
typedef struct AlterExtensionStmt
{
    NodeTag     type;
    char       *extname;
    List       *options;        /* List of DefElem nodes */
} AlterExtensionStmt;

typedef struct AlterExtensionContentsStmt
{
    NodeTag     type;
    char       *extname;        /* Extension's name */
    int         action;         /* +1 = add object, -1 = drop object */
    ObjectType  objtype;        /* Object's type */
    List       *objname;        /* Qualified name of the object */
    List       *objargs;        /* Arguments if needed (eg, for functions) */
} AlterExtensionContentsStmt;

/* ----------------------
 *      Create/Alter FOREIGN DATA WRAPPER Statements
 * ----------------------
 */

typedef struct CreateFdwStmt
{
    NodeTag     type;
    char       *fdwname;        /* foreign-data wrapper name */
    List       *func_options;   /* HANDLER/VALIDATOR options */
    List       *options;        /* generic options to FDW */
} CreateFdwStmt;

typedef struct AlterFdwStmt
{
    NodeTag     type;
    char       *fdwname;        /* foreign-data wrapper name */
    List       *func_options;   /* HANDLER/VALIDATOR options */
    List       *options;        /* generic options to FDW */
} AlterFdwStmt;

/* ----------------------
 *      Create/Alter FOREIGN SERVER Statements
 * ----------------------
 */

typedef struct CreateForeignServerStmt
{
    NodeTag     type;
    char       *servername;     /* server name */
    char       *servertype;     /* optional server type */
    char       *version;        /* optional server version */
    char       *fdwname;        /* FDW name */
    List       *options;        /* generic options to server */
} CreateForeignServerStmt;

typedef struct AlterForeignServerStmt
{
    NodeTag     type;
    char       *servername;     /* server name */
    char       *version;        /* optional server version */
    List       *options;        /* generic options to server */
    bool        has_version;    /* version specified */
} AlterForeignServerStmt;

/* ----------------------
 *      Create FOREIGN TABLE Statements
 * ----------------------
 */

typedef struct CreateForeignTableStmt
{
    CreateStmt  base;
    char       *servername;
    List       *options;
} CreateForeignTableStmt;

/* ----------------------
 *      Create/Drop USER MAPPING Statements
 * ----------------------
 */

typedef struct CreateUserMappingStmt
{
    NodeTag     type;
    char       *username;       /* username or PUBLIC/CURRENT_USER */
    char       *servername;     /* server name */
    List       *options;        /* generic options to server */
} CreateUserMappingStmt;

typedef struct AlterUserMappingStmt
{
    NodeTag     type;
    char       *username;       /* username or PUBLIC/CURRENT_USER */
    char       *servername;     /* server name */
    List       *options;        /* generic options to server */
} AlterUserMappingStmt;

typedef struct DropUserMappingStmt
{
    NodeTag     type;
    char       *username;       /* username or PUBLIC/CURRENT_USER */
    char       *servername;     /* server name */
    bool        missing_ok;     /* ignore missing mappings */
} DropUserMappingStmt;

/* ----------------------
 *      Create TRIGGER Statement
 * ----------------------
 */
typedef struct CreateTrigStmt
{
    NodeTag     type;
    char       *trigname;       /* TRIGGER's name */
    RangeVar   *relation;       /* relation trigger is on */
    List       *funcname;       /* qual. name of function to call */
    List       *args;           /* list of (T_String) Values or NIL */
    bool        row;            /* ROW/STATEMENT */
    /* timing uses the TRIGGER_TYPE bits defined in catalog/pg_trigger.h */
    int16       timing;         /* BEFORE, AFTER, or INSTEAD */
    /* events uses the TRIGGER_TYPE bits defined in catalog/pg_trigger.h */
    int16       events;         /* "OR" of INSERT/UPDATE/DELETE/TRUNCATE */
    List       *columns;        /* column names, or NIL for all columns */
    Node       *whenClause;     /* qual expression, or NULL if none */
    bool        isconstraint;   /* This is a constraint trigger */
    /* The remaining fields are only used for constraint triggers */
    bool        deferrable;     /* [NOT] DEFERRABLE */
    bool        initdeferred;   /* INITIALLY {DEFERRED|IMMEDIATE} */
    RangeVar   *constrrel;      /* opposite relation, if RI trigger */
} CreateTrigStmt;

/* ----------------------
 *      Create EVENT TRIGGER Statement
 * ----------------------
 */
typedef struct CreateEventTrigStmt
{
    NodeTag     type;
    char       *trigname;       /* TRIGGER's name */
    char       *eventname;      /* event's identifier */
    List       *whenclause;     /* list of DefElems indicating filtering */
    List       *funcname;       /* qual. name of function to call */
} CreateEventTrigStmt;

/* ----------------------
 *      Alter EVENT TRIGGER Statement
 * ----------------------
 */
typedef struct AlterEventTrigStmt
{
    NodeTag     type;
    char       *trigname;       /* TRIGGER's name */
    char        tgenabled;      /* trigger's firing configuration WRT
                                 * session_replication_role */
} AlterEventTrigStmt;

/* ----------------------
 *      Create/Drop PROCEDURAL LANGUAGE Statements
 *      Create PROCEDURAL LANGUAGE Statements
 * ----------------------
 */
typedef struct CreatePLangStmt
{
    NodeTag     type;
    bool        replace;        /* T => replace if already exists */
    char       *plname;         /* PL name */
    List       *plhandler;      /* PL call handler function (qual. name) */
    List       *plinline;       /* optional inline function (qual. name) */
    List       *plvalidator;    /* optional validator function (qual. name) */
    bool        pltrusted;      /* PL is trusted */
} CreatePLangStmt;

/* ----------------------
 *  Create/Alter/Drop Role Statements
 *
 * Note: these node types are also used for the backwards-compatible
 * Create/Alter/Drop User/Group statements.  In the ALTER and DROP cases
 * there's really no need to distinguish what the original spelling was,
 * but for CREATE we mark the type because the defaults vary.
 * ----------------------
 */
typedef enum RoleStmtType
{
    ROLESTMT_ROLE,
    ROLESTMT_USER,
    ROLESTMT_GROUP
} RoleStmtType;

typedef struct CreateRoleStmt
{
    NodeTag     type;
    RoleStmtType stmt_type;     /* ROLE/USER/GROUP */
    char       *role;           /* role name */
    List       *options;        /* List of DefElem nodes */
} CreateRoleStmt;

typedef struct AlterRoleStmt
{
    NodeTag     type;
    char       *role;           /* role name */
    List       *options;        /* List of DefElem nodes */
    int         action;         /* +1 = add members, -1 = drop members */
} AlterRoleStmt;

typedef struct AlterRoleSetStmt
{
    NodeTag     type;
    char       *role;           /* role name */
    char       *database;       /* database name, or NULL */
    VariableSetStmt *setstmt;   /* SET or RESET subcommand */
} AlterRoleSetStmt;

typedef struct DropRoleStmt
{
    NodeTag     type;
    List       *roles;          /* List of roles to remove */
    bool        missing_ok;     /* skip error if a role is missing? */
} DropRoleStmt;

/* ----------------------
 *      {Create|Alter} SEQUENCE Statement
 * ----------------------
 */

typedef struct CreateSeqStmt
{
    NodeTag     type;
    RangeVar   *sequence;       /* the sequence to create */
    List       *options;
    Oid         ownerId;        /* ID of owner, or InvalidOid for default */
} CreateSeqStmt;

typedef struct AlterSeqStmt
{
    NodeTag     type;
    RangeVar   *sequence;       /* the sequence to alter */
    List       *options;
    bool        missing_ok;     /* skip error if a role is missing? */
} AlterSeqStmt;

/* ----------------------
 *      Create {Aggregate|Operator|Type} Statement
 * ----------------------
 */
typedef struct DefineStmt
{
    NodeTag     type;
    ObjectType  kind;           /* aggregate, operator, type */
    bool        oldstyle;       /* hack to signal old CREATE AGG syntax */
    List       *defnames;       /* qualified name (list of Value strings) */
    List       *args;           /* a list of TypeName (if needed) */
    List       *definition;     /* a list of DefElem */
} DefineStmt;

/* ----------------------
 *      Create Domain Statement
 * ----------------------
 */
typedef struct CreateDomainStmt
{
    NodeTag     type;
    List       *domainname;     /* qualified name (list of Value strings) */
    TypeName   *typeName;       /* the base type */
    CollateClause *collClause;  /* untransformed COLLATE spec, if any */
    List       *constraints;    /* constraints (list of Constraint nodes) */
} CreateDomainStmt;

/* ----------------------
 *      Create Operator Class Statement
 * ----------------------
 */
typedef struct CreateOpClassStmt
{
    NodeTag     type;
    List       *opclassname;    /* qualified name (list of Value strings) */
    List       *opfamilyname;   /* qualified name (ditto); NIL if omitted */
    char       *amname;         /* name of index AM opclass is for */
    TypeName   *datatype;       /* datatype of indexed column */
    List       *items;          /* List of CreateOpClassItem nodes */
    bool        isDefault;      /* Should be marked as default for type? */
} CreateOpClassStmt;

#define OPCLASS_ITEM_OPERATOR       1
#define OPCLASS_ITEM_FUNCTION       2
#define OPCLASS_ITEM_STORAGETYPE    3

typedef struct CreateOpClassItem
{
    NodeTag     type;
    int         itemtype;       /* see codes above */
    /* fields used for an operator or function item: */
    List       *name;           /* operator or function name */
    List       *args;           /* argument types */
    int         number;         /* strategy num or support proc num */
    List       *order_family;   /* only used for ordering operators */
    List       *class_args;     /* only used for functions */
    /* fields used for a storagetype item: */
    TypeName   *storedtype;     /* datatype stored in index */
} CreateOpClassItem;

/* ----------------------
 *      Create Operator Family Statement
 * ----------------------
 */
typedef struct CreateOpFamilyStmt
{
    NodeTag     type;
    List       *opfamilyname;   /* qualified name (list of Value strings) */
    char       *amname;         /* name of index AM opfamily is for */
} CreateOpFamilyStmt;

/* ----------------------
 *      Alter Operator Family Statement
 * ----------------------
 */
typedef struct AlterOpFamilyStmt
{
    NodeTag     type;
    List       *opfamilyname;   /* qualified name (list of Value strings) */
    char       *amname;         /* name of index AM opfamily is for */
    bool        isDrop;         /* ADD or DROP the items? */
    List       *items;          /* List of CreateOpClassItem nodes */
} AlterOpFamilyStmt;

/* ----------------------
 *      Drop Table|Sequence|View|Index|Type|Domain|Conversion|Schema Statement
 * ----------------------
 */

typedef struct DropStmt
{
    NodeTag     type;
    List       *objects;        /* list of sublists of names (as Values) */
    List       *arguments;      /* list of sublists of arguments (as Values) */
    ObjectType  removeType;     /* object type */
    DropBehavior behavior;      /* RESTRICT or CASCADE behavior */
    bool        missing_ok;     /* skip error if object is missing? */
    bool        concurrent;     /* drop index concurrently? */
} DropStmt;

/* ----------------------
 *              Truncate Table Statement
 * ----------------------
 */
typedef struct TruncateStmt
{
    NodeTag     type;
    List       *relations;      /* relations (RangeVars) to be truncated */
    bool        restart_seqs;   /* restart owned sequences? */
    DropBehavior behavior;      /* RESTRICT or CASCADE behavior */
} TruncateStmt;

/* ----------------------
 *              Comment On Statement
 * ----------------------
 */
typedef struct CommentStmt
{
    NodeTag     type;
    ObjectType  objtype;        /* Object's type */
    List       *objname;        /* Qualified name of the object */
    List       *objargs;        /* Arguments if needed (eg, for functions) */
    char       *comment;        /* Comment to insert, or NULL to remove */
} CommentStmt;

/* ----------------------
 *              SECURITY LABEL Statement
 * ----------------------
 */
typedef struct SecLabelStmt
{
    NodeTag     type;
    ObjectType  objtype;        /* Object's type */
    List       *objname;        /* Qualified name of the object */
    List       *objargs;        /* Arguments if needed (eg, for functions) */
    char       *provider;       /* Label provider (or NULL) */
    char       *label;          /* New security label to be assigned */
} SecLabelStmt;

/* ----------------------
 *      Declare Cursor Statement
 *
 * Note: the "query" field of DeclareCursorStmt is only used in the raw grammar
 * output.  After parse analysis it's set to null, and the Query points to the
 * DeclareCursorStmt, not vice versa.
 * ----------------------
 */
#define CURSOR_OPT_BINARY       0x0001  /* BINARY */
#define CURSOR_OPT_SCROLL       0x0002  /* SCROLL explicitly given */
#define CURSOR_OPT_NO_SCROLL    0x0004  /* NO SCROLL explicitly given */
#define CURSOR_OPT_INSENSITIVE  0x0008  /* INSENSITIVE */
#define CURSOR_OPT_HOLD         0x0010  /* WITH HOLD */
/* these planner-control flags do not correspond to any SQL grammar: */
#define CURSOR_OPT_FAST_PLAN    0x0020  /* prefer fast-start plan */
#define CURSOR_OPT_GENERIC_PLAN 0x0040  /* force use of generic plan */
#define CURSOR_OPT_CUSTOM_PLAN  0x0080  /* force use of custom plan */

typedef struct DeclareCursorStmt
{
    NodeTag     type;
    char       *portalname;     /* name of the portal (cursor) */
    int         options;        /* bitmask of options (see above) */
    Node       *query;          /* the raw SELECT query */
} DeclareCursorStmt;

/* ----------------------
 *      Close Portal Statement
 * ----------------------
 */
typedef struct ClosePortalStmt
{
    NodeTag     type;
    char       *portalname;     /* name of the portal (cursor) */
    /* NULL means CLOSE ALL */
} ClosePortalStmt;

/* ----------------------
 *      Fetch Statement (also Move)
 * ----------------------
 */
typedef enum FetchDirection
{
    /* for these, howMany is how many rows to fetch; FETCH_ALL means ALL */
    FETCH_FORWARD,
    FETCH_BACKWARD,
    /* for these, howMany indicates a position; only one row is fetched */
    FETCH_ABSOLUTE,
    FETCH_RELATIVE
} FetchDirection;

#define FETCH_ALL   LONG_MAX

typedef struct FetchStmt
{
    NodeTag     type;
    FetchDirection direction;   /* see above */
    long        howMany;        /* number of rows, or position argument */
    char       *portalname;     /* name of portal (cursor) */
    bool        ismove;         /* TRUE if MOVE */
} FetchStmt;

/* ----------------------
 *      Create Index Statement
 *
 * This represents creation of an index and/or an associated constraint.
 * If isconstraint is true, we should create a pg_constraint entry along
 * with the index.  But if indexOid isn't InvalidOid, we are not creating an
 * index, just a UNIQUE/PKEY constraint using an existing index.  isconstraint
 * must always be true in this case, and the fields describing the index
 * properties are empty.
 * ----------------------
 */
typedef struct IndexStmt
{
    NodeTag     type;
    char       *idxname;        /* name of new index, or NULL for default */
    RangeVar   *relation;       /* relation to build index on */
    char       *accessMethod;   /* name of access method (eg. btree) */
    char       *tableSpace;     /* tablespace, or NULL for default */
    List       *indexParams;    /* columns to index: a list of IndexElem */
    List       *options;        /* WITH clause options: a list of DefElem */
    Node       *whereClause;    /* qualification (partial-index predicate) */
    List       *excludeOpNames; /* exclusion operator names, or NIL if none */
    char       *idxcomment;     /* comment to apply to index, or NULL */
    Oid         indexOid;       /* OID of an existing index, if any */
    Oid         oldNode;        /* relfilenode of existing storage, if any */
    bool        unique;         /* is index unique? */
    bool        primary;        /* is index a primary key? */
    bool        isconstraint;   /* is it for a pkey/unique constraint? */
    bool        deferrable;     /* is the constraint DEFERRABLE? */
    bool        initdeferred;   /* is the constraint INITIALLY DEFERRED? */
    bool        concurrent;     /* should this be a concurrent index build? */
} IndexStmt;

/* ----------------------
 *      Create Function Statement
 * ----------------------
 */
typedef struct CreateFunctionStmt
{
    NodeTag     type;
    bool        replace;        /* T => replace if already exists */
    List       *funcname;       /* qualified name of function to create */
    List       *parameters;     /* a list of FunctionParameter */
    TypeName   *returnType;     /* the return type */
    List       *options;        /* a list of DefElem */
    List       *withClause;     /* a list of DefElem */
} CreateFunctionStmt;

typedef enum FunctionParameterMode
{
    /* the assigned enum values appear in pg_proc, don't change 'em! */
    FUNC_PARAM_IN = 'i',        /* input only */
    FUNC_PARAM_OUT = 'o',       /* output only */
    FUNC_PARAM_INOUT = 'b',     /* both */
    FUNC_PARAM_VARIADIC = 'v',  /* variadic (always input) */
    FUNC_PARAM_TABLE = 't'      /* table function output column */
} FunctionParameterMode;

typedef struct FunctionParameter
{
    NodeTag     type;
    char       *name;           /* parameter name, or NULL if not given */
    TypeName   *argType;        /* TypeName for parameter type */
    FunctionParameterMode mode; /* IN/OUT/etc */
    Node       *defexpr;        /* raw default expr, or NULL if not given */
} FunctionParameter;

typedef struct AlterFunctionStmt
{
    NodeTag     type;
    FuncWithArgs *func;         /* name and args of function */
    List       *actions;        /* list of DefElem */
} AlterFunctionStmt;

/* ----------------------
 *      DO Statement
 *
 * DoStmt is the raw parser output, InlineCodeBlock is the execution-time API
 * ----------------------
 */
typedef struct DoStmt
{
    NodeTag     type;
    List       *args;           /* List of DefElem nodes */
} DoStmt;

typedef struct InlineCodeBlock
{
    NodeTag     type;
    char       *source_text;    /* source text of anonymous code block */
    Oid         langOid;        /* OID of selected language */
    bool        langIsTrusted;  /* trusted property of the language */
} InlineCodeBlock;

/* ----------------------
 *      Alter Object Rename Statement
 * ----------------------
 */
typedef struct RenameStmt
{
    NodeTag     type;
    ObjectType  renameType;     /* OBJECT_TABLE, OBJECT_COLUMN, etc */
    ObjectType  relationType;   /* if column name, associated relation type */
    RangeVar   *relation;       /* in case it's a table */
    List       *object;         /* in case it's some other object */
    List       *objarg;         /* argument types, if applicable */
    char       *subname;        /* name of contained object (column, rule,
                                 * trigger, etc) */
    char       *newname;        /* the new name */
    DropBehavior behavior;      /* RESTRICT or CASCADE behavior */
    bool        missing_ok;     /* skip error if missing? */
} RenameStmt;

/* ----------------------
 *      ALTER object SET SCHEMA Statement
 * ----------------------
 */
typedef struct AlterObjectSchemaStmt
{
    NodeTag     type;
    ObjectType objectType;      /* OBJECT_TABLE, OBJECT_TYPE, etc */
    RangeVar   *relation;       /* in case it's a table */
    List       *object;         /* in case it's some other object */
    List       *objarg;         /* argument types, if applicable */
    char       *newschema;      /* the new schema */
    bool        missing_ok;     /* skip error if missing? */
} AlterObjectSchemaStmt;

/* ----------------------
 *      Alter Object Owner Statement
 * ----------------------
 */
typedef struct AlterOwnerStmt
{
    NodeTag     type;
    ObjectType objectType;      /* OBJECT_TABLE, OBJECT_TYPE, etc */
    RangeVar   *relation;       /* in case it's a table */
    List       *object;         /* in case it's some other object */
    List       *objarg;         /* argument types, if applicable */
    char       *newowner;       /* the new owner */
} AlterOwnerStmt;


/* ----------------------
 *      Create Rule Statement
 * ----------------------
 */
typedef struct RuleStmt
{
    NodeTag     type;
    RangeVar   *relation;       /* relation the rule is for */
    char       *rulename;       /* name of the rule */
    Node       *whereClause;    /* qualifications */
    CmdType     event;          /* SELECT, INSERT, etc */
    bool        instead;        /* is a 'do instead'? */
    List       *actions;        /* the action statements */
    bool        replace;        /* OR REPLACE */
} RuleStmt;

/* ----------------------
 *      Notify Statement
 * ----------------------
 */
typedef struct NotifyStmt
{
    NodeTag     type;
    char       *conditionname;  /* condition name to notify */
    char       *payload;        /* the payload string, or NULL if none */
} NotifyStmt;

/* ----------------------
 *      Listen Statement
 * ----------------------
 */
typedef struct ListenStmt
{
    NodeTag     type;
    char       *conditionname;  /* condition name to listen on */
} ListenStmt;

/* ----------------------
 *      Unlisten Statement
 * ----------------------
 */
typedef struct UnlistenStmt
{
    NodeTag     type;
    char       *conditionname;  /* name to unlisten on, or NULL for all */
} UnlistenStmt;

/* ----------------------
 *      {Begin|Commit|Rollback} Transaction Statement
 * ----------------------
 */
typedef enum TransactionStmtKind
{
    TRANS_STMT_BEGIN,
    TRANS_STMT_START,           /* semantically identical to BEGIN */
    TRANS_STMT_COMMIT,
    TRANS_STMT_ROLLBACK,
    TRANS_STMT_SAVEPOINT,
    TRANS_STMT_RELEASE,
    TRANS_STMT_ROLLBACK_TO,
    TRANS_STMT_PREPARE,
    TRANS_STMT_COMMIT_PREPARED,
    TRANS_STMT_ROLLBACK_PREPARED
} TransactionStmtKind;

typedef struct TransactionStmt
{
    NodeTag     type;
    TransactionStmtKind kind;   /* see above */
    List       *options;        /* for BEGIN/START and savepoint commands */
    char       *gid;            /* for two-phase-commit related commands */
} TransactionStmt;

/* ----------------------
 *      Create Type Statement, composite types
 * ----------------------
 */
typedef struct CompositeTypeStmt
{
    NodeTag     type;
    RangeVar   *typevar;        /* the composite type to be created */
    List       *coldeflist;     /* list of ColumnDef nodes */
} CompositeTypeStmt;

/* ----------------------
 *      Create Type Statement, enum types
 * ----------------------
 */
typedef struct CreateEnumStmt
{
    NodeTag     type;
    List       *typeName;       /* qualified name (list of Value strings) */
    List       *vals;           /* enum values (list of Value strings) */
} CreateEnumStmt;

/* ----------------------
 *      Create Type Statement, range types
 * ----------------------
 */
typedef struct CreateRangeStmt
{
    NodeTag     type;
    List       *typeName;       /* qualified name (list of Value strings) */
    List       *params;         /* range parameters (list of DefElem) */
} CreateRangeStmt;

/* ----------------------
 *      Alter Type Statement, enum types
 * ----------------------
 */
typedef struct AlterEnumStmt
{
    NodeTag     type;
    List       *typeName;       /* qualified name (list of Value strings) */
    char       *newVal;         /* new enum value's name */
    char       *newValNeighbor; /* neighboring enum value, if specified */
    bool        newValIsAfter;  /* place new enum value after neighbor? */
    bool        skipIfExists;   /* no error if label already exists */
} AlterEnumStmt;

/* ----------------------
 *      Create View Statement
 * ----------------------
 */
typedef struct ViewStmt
{
    NodeTag     type;
    RangeVar   *view;           /* the view to be created */
    List       *aliases;        /* target column names */
    Node       *query;          /* the SELECT query */
    bool        replace;        /* replace an existing view? */
    List       *options;        /* options from WITH clause */
} ViewStmt;

/* ----------------------
 *      Load Statement
 * ----------------------
 */
typedef struct LoadStmt
{
    NodeTag     type;
    char       *filename;       /* file to load */
} LoadStmt;

/* ----------------------
 *      Createdb Statement
 * ----------------------
 */
typedef struct CreatedbStmt
{
    NodeTag     type;
    char       *dbname;         /* name of database to create */
    List       *options;        /* List of DefElem nodes */
} CreatedbStmt;

/* ----------------------
 *  Alter Database
 * ----------------------
 */
typedef struct AlterDatabaseStmt
{
    NodeTag     type;
    char       *dbname;         /* name of database to alter */
    List       *options;        /* List of DefElem nodes */
} AlterDatabaseStmt;

typedef struct AlterDatabaseSetStmt
{
    NodeTag     type;
    char       *dbname;         /* database name */
    VariableSetStmt *setstmt;   /* SET or RESET subcommand */
} AlterDatabaseSetStmt;

/* ----------------------
 *      Dropdb Statement
 * ----------------------
 */
typedef struct DropdbStmt
{
    NodeTag     type;
    char       *dbname;         /* database to drop */
    bool        missing_ok;     /* skip error if db is missing? */
} DropdbStmt;

/* ----------------------
 *      Cluster Statement (support pbrown's cluster index implementation)
 * ----------------------
 */
typedef struct ClusterStmt
{
    NodeTag     type;
    RangeVar   *relation;       /* relation being indexed, or NULL if all */
    char       *indexname;      /* original index defined */
    bool        verbose;        /* print progress info */
} ClusterStmt;

/* ----------------------
 *      Vacuum and Analyze Statements
 *
 * Even though these are nominally two statements, it's convenient to use
 * just one node type for both.  Note that at least one of VACOPT_VACUUM
 * and VACOPT_ANALYZE must be set in options.  VACOPT_FREEZE is an internal
 * convenience for the grammar and is not examined at runtime --- the
 * freeze_min_age and freeze_table_age fields are what matter.
 * ----------------------
 */
typedef enum VacuumOption
{
    VACOPT_VACUUM = 1 << 0,     /* do VACUUM */
    VACOPT_ANALYZE = 1 << 1,    /* do ANALYZE */
    VACOPT_VERBOSE = 1 << 2,    /* print progress info */
    VACOPT_FREEZE = 1 << 3,     /* FREEZE option */
    VACOPT_FULL = 1 << 4,       /* FULL (non-concurrent) vacuum */
    VACOPT_NOWAIT = 1 << 5      /* don't wait to get lock (autovacuum only) */
} VacuumOption;

typedef struct VacuumStmt
{
    NodeTag     type;
    int         options;        /* OR of VacuumOption flags */
    int         freeze_min_age; /* min freeze age, or -1 to use default */
    int         freeze_table_age;       /* age at which to scan whole table */
    RangeVar   *relation;       /* single table to process, or NULL */
    List       *va_cols;        /* list of column names, or NIL for all */
} VacuumStmt;

/* ----------------------
 *      Explain Statement
 *
 * The "query" field is either a raw parse tree (SelectStmt, InsertStmt, etc)
 * or a Query node if parse analysis has been done.  Note that rewriting and
 * planning of the query are always postponed until execution of EXPLAIN.
 * ----------------------
 */
typedef struct ExplainStmt
{
    NodeTag     type;
    Node       *query;          /* the query (see comments above) */
    List       *options;        /* list of DefElem nodes */
} ExplainStmt;

/* ----------------------
 *      CREATE TABLE AS Statement (a/k/a SELECT INTO)
 *
 * A query written as CREATE TABLE AS will produce this node type natively.
 * A query written as SELECT ... INTO will be transformed to this form during
 * parse analysis.
 * A query written as CREATE MATERIALIZED view will produce this node type,
 * during parse analysis, since it needs all the same data.
 *
 * The "query" field is handled similarly to EXPLAIN, though note that it
 * can be a SELECT or an EXECUTE, but not other DML statements.
 * ----------------------
 */
typedef struct CreateTableAsStmt
{
    NodeTag     type;
    Node       *query;          /* the query (see comments above) */
    IntoClause *into;           /* destination table */
    ObjectType  relkind;        /* OBJECT_TABLE or OBJECT_MATVIEW */
    bool        is_select_into; /* it was written as SELECT INTO */
} CreateTableAsStmt;

/* ----------------------
 *      REFRESH MATERIALIZED VIEW Statement
 * ----------------------
 */
typedef struct RefreshMatViewStmt
{
    NodeTag     type;
    bool        skipData;       /* true for WITH NO DATA */
    RangeVar   *relation;       /* relation to insert into */
} RefreshMatViewStmt;

/* ----------------------
 * Checkpoint Statement
 * ----------------------
 */
typedef struct CheckPointStmt
{
    NodeTag     type;
} CheckPointStmt;

/* ----------------------
 * Discard Statement
 * ----------------------
 */

typedef enum DiscardMode
{
    DISCARD_ALL,
    DISCARD_PLANS,
    DISCARD_TEMP
} DiscardMode;

typedef struct DiscardStmt
{
    NodeTag     type;
    DiscardMode target;
} DiscardStmt;

/* ----------------------
 *      LOCK Statement
 * ----------------------
 */
typedef struct LockStmt
{
    NodeTag     type;
    List       *relations;      /* relations to lock */
    int         mode;           /* lock mode */
    bool        nowait;         /* no wait mode */
} LockStmt;

/* ----------------------
 *      SET CONSTRAINTS Statement
 * ----------------------
 */
typedef struct ConstraintsSetStmt
{
    NodeTag     type;
    List       *constraints;    /* List of names as RangeVars */
    bool        deferred;
} ConstraintsSetStmt;

/* ----------------------
 *      REINDEX Statement
 * ----------------------
 */
typedef struct ReindexStmt
{
    NodeTag     type;
    ObjectType  kind;           /* OBJECT_INDEX, OBJECT_TABLE, etc. */
    RangeVar   *relation;       /* Table or index to reindex */
    const char *name;           /* name of database to reindex */
    bool        do_system;      /* include system tables in database case */
    bool        do_user;        /* include user tables in database case */
} ReindexStmt;

/* ----------------------
 *      CREATE CONVERSION Statement
 * ----------------------
 */
typedef struct CreateConversionStmt
{
    NodeTag     type;
    List       *conversion_name;    /* Name of the conversion */
    char       *for_encoding_name;      /* source encoding name */
    char       *to_encoding_name;       /* destination encoding name */
    List       *func_name;      /* qualified conversion function name */
    bool        def;            /* is this a default conversion? */
} CreateConversionStmt;

/* ----------------------
 *  CREATE CAST Statement
 * ----------------------
 */
typedef struct CreateCastStmt
{
    NodeTag     type;
    TypeName   *sourcetype;
    TypeName   *targettype;
    FuncWithArgs *func;
    CoercionContext context;
    bool        inout;
} CreateCastStmt;

/* ----------------------
 *      PREPARE Statement
 * ----------------------
 */
typedef struct PrepareStmt
{
    NodeTag     type;
    char       *name;           /* Name of plan, arbitrary */
    List       *argtypes;       /* Types of parameters (List of TypeName) */
    Node       *query;          /* The query itself (as a raw parsetree) */
} PrepareStmt;


/* ----------------------
 *      EXECUTE Statement
 * ----------------------
 */

typedef struct ExecuteStmt
{
    NodeTag     type;
    char       *name;           /* The name of the plan to execute */
    List       *params;         /* Values to assign to parameters */
} ExecuteStmt;


/* ----------------------
 *      DEALLOCATE Statement
 * ----------------------
 */
typedef struct DeallocateStmt
{
    NodeTag     type;
    char       *name;           /* The name of the plan to remove */
    /* NULL means DEALLOCATE ALL */
} DeallocateStmt;

/*
 *      DROP OWNED statement
 */
typedef struct DropOwnedStmt
{
    NodeTag     type;
    List       *roles;
    DropBehavior behavior;
} DropOwnedStmt;

/*
 *      REASSIGN OWNED statement
 */
typedef struct ReassignOwnedStmt
{
    NodeTag     type;
    List       *roles;
    char       *newrole;
} ReassignOwnedStmt;

/*
 * TS Dictionary stmts: DefineStmt, RenameStmt and DropStmt are default
 */
typedef struct AlterTSDictionaryStmt
{
    NodeTag     type;
    List       *dictname;       /* qualified name (list of Value strings) */
    List       *options;        /* List of DefElem nodes */
} AlterTSDictionaryStmt;

/*
 * TS Configuration stmts: DefineStmt, RenameStmt and DropStmt are default
 */
typedef struct AlterTSConfigurationStmt
{
    NodeTag     type;
    List       *cfgname;        /* qualified name (list of Value strings) */

    /*
     * dicts will be non-NIL if ADD/ALTER MAPPING was specified. If dicts is
     * NIL, but tokentype isn't, DROP MAPPING was specified.
     */
    List       *tokentype;      /* list of Value strings */
    List       *dicts;          /* list of list of Value strings */
    bool        override;       /* if true - remove old variant */
    bool        replace;        /* if true - replace dictionary by another */
    bool        missing_ok;     /* for DROP - skip error if missing? */
} AlterTSConfigurationStmt;

#endif   /* PARSENODES_H */