#include <D32DBMS.H>
Link against:
edbms.lib
class CDbColSet : public CBase;
Description
Manages a set of column definitions which describe a table or rowset structure. Column definitions can be added and removed.
The set can be iterated over, and ordinals for a column can be looked up.
The class is not intended for user derivation.
Derivation
CBase
-
Base class for all classes to be instantiated on the heap.
CDbColSet
- Manages a set of column definitions which describe a table or rowset structure. ...
Members
Defined in CDbColSet
:
Inherited from CBase
:
Construction and destruction
IMPORT_C CDbColSet();
Description
Constructs an empty column set.
IMPORT_C static CDbColSet* NewL();
Description
Constructs a new empty column set and returns a pointer to it.
Return value
CDbColSet *
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A pointer to the column set object.
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IMPORT_C static CDbColSet* NewLC();
Description
Constructs a new empty column set and returns a pointer to it — placing the pointer onto the cleanup stack. This allows
the column set object and allocated resources to be cleaned up if a subsequent leave occurs.
Return value
CDbColSet *
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A pointer to the column set object.
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IMPORT_C ~CDbColSet();
Description
Frees resources owned by the object.
operator[](TDbColNo)const
inline const TDbCol& operator[](TDbColNo aCol) const;
Description
Returns a column definition by its ordinal number in the set.
Note that using a TDbColSetIter
is another way to iterate through the contents of a CDbColSet.
Parameters
TDbColNo aCol |
The ordinal number of the column in the set. Columns in a column set are numbered from 1 to CDbColSet::Count()const , unlike Symbian OS array classes. Ordinal 0 is reserved to represent the invalid column number KDbNullColNo.
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Return value
const TDbCol & |
The column definition requested.
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IMPORT_C const TDbCol* Col(const TDesC &aColName) const;
Description
Returns a named column definition in the set. If such a column does not exist in the set NULL is returned.
Parameters
const TDesC16 &aColName |
The name of the column to find.
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Return value
const TDbCol * |
A pointer to the column definition found, or NULL.
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ColNo(const TDesC &)const
IMPORT_C TDbColNo ColNo(const TDesC &aColName) const;
Description
Returns the ordinal for a particular column name in this column set. If such a column does not exist in the set the special
ordinal KDbNullColNo is returned.
This function is particularly important when accessing data through a rowset. If the set of columns to be returned by a rowset
is not explicitly specified, no assumptions should be made about the ordering of the columns returned. In such a case, in
order to access the column data a column ordinal is required, and this can be obtained by using this function on the column
set returned by RDbRowSet::ColSetL()const
.
Parameters
const TDesC16 &aColName |
The name of the column to find.
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Return value
TDbColNo
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The ordinal number of the column.
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inline TInt Count() const;
Description
Returns the number of column definitions in the set.
Note that using a TDbColSetIter
is another way to iterate through the contents of a CDbColSet.
Return value
TInt
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The number of columns in the columns set.
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inline void Clear();
Description
Removes all of the columns from the column set.
IMPORT_C CDbColSet& AddL(const TDbCol &aCol);
Description
Adds a column to the column set.
Parameters
const TDbCol &aCol |
The column to add to the set.
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Return value
IMPORT_C void Remove(const TDesC &aColName);
Description
Removes the named column from the set.
Parameters
const TDesC16 &aColName |
The name of the column to remove from the set.
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