QSqlIndex Class

The QSqlIndex class provides functions to manipulate and describe database indexes. 更多...

Header: #include <QSqlIndex>
CMake: find_package(Qt6 COMPONENTS Sql REQUIRED)
target_link_libraries(mytarget PRIVATE Qt6::Sql)
qmake: QT += sql
继承: QSqlRecord

公共函数

QSqlIndex (const QSqlIndex & other )
QSqlIndex (const QString & cursorname = QString(), const QString & name = QString())
QSqlIndex & operator= (const QSqlIndex & other )
~QSqlIndex ()
void append (const QSqlField & field )
void append (const QSqlField & field , bool desc )
QString cursorName () const
bool isDescending (int i ) const
QString name () const
void setCursorName (const QString & cursorName )
void setDescending (int i , bool desc )
void setName (const QString & name )

详细描述

An index refers to a single table or view in a database. Information about the fields that comprise the index can be used to generate SQL statements.

成员函数文档编制

QSqlIndex:: QSqlIndex (const QSqlIndex & other )

构造副本为 other .

QSqlIndex:: QSqlIndex (const QString & cursorname = QString(), const QString & name = QString())

Constructs an empty index using the cursor name cursorname and index name name .

QSqlIndex &QSqlIndex:: operator= (const QSqlIndex & other )

Sets the index equal to other .

QSqlIndex:: ~QSqlIndex ()

销毁对象并释放任何分配资源。

void QSqlIndex:: append (const QSqlField & field )

Appends the field field to the list of indexed fields. The field is appended with an ascending sort order.

void QSqlIndex:: append (const QSqlField & field , bool desc )

这是重载函数。

Appends the field field to the list of indexed fields. The field is appended with an ascending sort order, unless desc 为 true。

QString QSqlIndex:: cursorName () const

Returns the name of the cursor which the index is associated with.

另请参阅 setCursorName ().

bool QSqlIndex:: isDescending ( int i ) const

返回 true if field i in the index is sorted in descending order; otherwise returns false .

QString QSqlIndex:: name () const

Returns the name of the index.

另请参阅 setName ().

void QSqlIndex:: setCursorName (const QString & cursorName )

Sets the name of the cursor that the index is associated with to cursorName .

另请参阅 cursorName ().

void QSqlIndex:: setDescending ( int i , bool desc )

desc is true, field i is sorted in descending order. Otherwise, field i is sorted in ascending order (the default). If the field does not exist, nothing happens.

另请参阅 isDescending ().

void QSqlIndex:: setName (const QString & name )

Sets the name of the index to name .

另请参阅 name ().