|
Home · All Namespaces · All Classes · Main Classes · Grouped Classes · Modules · Functions |
The Q3SqlFieldInfo class stores meta data associated with a SQL field. More...
#include <Q3SqlFieldInfo>
This class is part of the Qt 3 support library. It is provided to keep old source code working. We strongly advise against using it in new code. See Porting to Qt 4 for more information.
The Q3SqlFieldInfo class stores meta data associated with a SQL field.
Q3SqlFieldInfo objects only store meta data; field values are stored in QSqlField objects.
All values must be set in the constructor, and may be retrieved using isRequired(), type(), length(), precision(), defaultValue(), name(), isGenerated() and typeID().
See also Q3SqlRecordInfo.
Constructs a Q3SqlFieldInfo with the following parameters:
| name | the name of the field. |
| typ | the field's type in a QVariant. |
| required | greater than 0 if the field is required, 0 if its value can be NULL and less than 0 if it cannot be determined whether the field is required or not. |
| len | the length of the field. Note that for non-character types some databases return either the length in bytes or the number of digits. -1 signifies that the length cannot be determined. |
| prec | the precision of the field, or -1 if the field has no precision or it cannot be determined. |
| defValue | the default value that is inserted into the table if none is specified by the user. QVariant() if there is no default value or it cannot be determined. |
| typeID | the internal typeID of the database system (only useful for low-level programming). 0 if unknown. |
| generated | TRUE indicates that this field should be included in auto-generated SQL statments, e.g. in Q3SqlCursor. |
| trim | TRUE indicates that widgets should remove trailing whitespace from character fields. This does not affect the field value but only its representation inside widgets. |
| calculated | TRUE indicates that the value of this field is calculated. The value of calculated fields can by modified by subclassing Q3SqlCursor and overriding Q3SqlCursor::calculateField(). |
Creates a Q3SqlFieldInfo object with the type and the name of the QSqlField other.
Destroys the object and frees any allocated resources.
Returns the field's default value or an empty QVariant if the field has no default value or the value couldn't be determined. The default value is the value inserted in the database when it is not explicitly specified by the user.
Returns TRUE if the field is calculated; otherwise returns FALSE.
See also setCalculated().
Returns TRUE if the field should be included in auto-generated SQL statments, e.g. in Q3SqlCursor; otherwise returns FALSE.
See also setGenerated().
Returns a value greater than 0 if the field is required (NULL values are not allowed), 0 if it isn't required (NULL values are allowed) or less than 0 if it cannot be determined whether the field is required or not.
Returns TRUE if trailing whitespace should be removed from character fields; otherwise returns FALSE.
See also setTrim().
Returns the field's length. For fields storing text the return value is the maximum number of characters the field can hold. For non-character fields some database systems return the number of bytes needed or the number of digits allowed. If the length cannot be determined -1 is returned.
Returns the name of the field in the SQL table.
Returns the field's precision or -1 if the field has no precision or it cannot be determined.
calculated set to TRUE indicates that this field is a calculated field. The value of calculated fields can by modified by subclassing Q3SqlCursor and overriding Q3SqlCursor::calculateField().
See also isCalculated().
generated set to FALSE indicates that this field should not appear in auto-generated SQL statements (for example in Q3SqlCursor).
See also isGenerated().
If trim is TRUE widgets should remove trailing whitespace from character fields. This does not affect the field value but only its representation inside widgets.
See also isTrim().
Returns an empty QSqlField based on the information in this Q3SqlFieldInfo.
Returns the field's type or QVariant::Invalid if the type is unknown.
Returns the internal type identifier as returned from the database system. The return value is 0 if the type is unknown.
Assigns other to this field info and returns a reference to it.
| Copyright © 2009 Nokia Corporation and/or its subsidiary(-ies) | Trademarks | Qt 4.5.1 |