QSqlRelation Class

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

头：	#include <QSqlRelation>
qmake:	QT += sql

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公共函数

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

详细描述

QSqlRelation is a helper class for QSqlRelationalTableModel 。见 QSqlRelationalTableModel::setRelation () 和 QSqlRelationalTableModel::relation () 了解细节。

另请参阅 QSqlRelationalTableModel , QSqlRelationalDelegate ，和关系表模型范例 .

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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.

另请参阅 tableName (), indexColumn ()，和 displayColumn ().

QSqlRelation:: QSqlRelation ()

Constructs an invalid QSqlRelation object.

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

另请参阅 isValid ().

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.

bool QSqlRelation:: isValid () const

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

void QSqlRelation:: swap ( QSqlRelation & other )

交换 this with other .

QString QSqlRelation:: tableName () const

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