QSqlRelation Class

The QSqlRelation class stores information about an SQL foreign key. 更多...

頭：	`#include <QSqlRelation>`
CMake:	`find_package(Qt6 REQUIRED COMPONENTS Sql)` `target_link_libraries(mytarget PRIVATE Qt6::Sql)`
qmake:	`QT += sql`

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公共函數

	QSqlRelation ()
	QSqlRelation (const QString & tableName , const QString & indexColumn , const QString & displayColumn )
QString	displayColumn () const
QString	indexColumn () const
bool	isValid () const
void	swap (QSqlRelation & other )
QString	tableName () const

詳細描述

QSqlRelation is a helper class for QSqlRelationalTableModel 。見 QSqlRelationalTableModel::setRelation () 和 QSqlRelationalTableModel::relation () 瞭解細節。

另請參閱 QSqlRelationalTableModel , QSqlRelationalDelegate ，和關係錶模型範例 .

成員函數文檔編製

QSqlRelation:: QSqlRelation ()

Constructs an invalid QSqlRelation object.

For such an object, the tableName (), indexColumn ()，和 displayColumn () functions return an empty string.

另請參閱 isValid ().

QSqlRelation:: QSqlRelation (const QString & tableName , const QString & indexColumn , const QString & displayColumn )

Constructs a QSqlRelation object, where tableName is the SQL table name to which a foreign key refers, indexColumn is the foreign key, and displayColumn is the field that should be presented to the user.

另請參閱 tableName (), indexColumn ()，和 displayColumn ().

QString QSqlRelation:: displayColumn () const

Returns the column from table tableName () that should be presented to the user instead of a foreign key.

QString QSqlRelation:: indexColumn () const

Returns the index column from table tableName () to which a foreign key refers.

`[noexcept]` bool QSqlRelation:: isValid () const

返迴 true 若 QSqlRelation object is valid; otherwise returns false .

`[noexcept]` void QSqlRelation:: swap ( QSqlRelation & other )

Swaps this relation with other 。此操作很快且從不失敗。

QString QSqlRelation:: tableName () const

Returns the name of the table to which a foreign key refers.