QSqlDatabase(3qt)

NAME
QSqlDatabase - Used to create SQL database connections and provide transaction handling

SYNOPSIS
#include <qsqldatabase.h>

Inherits QObject.

  Public Members
~QSqlDatabase ()
bool open ()
bool open ( const QString & user, const QString & password )
void close ()
bool isOpen () const
bool isOpenError () const
QStringList tables () const
QSqlIndex primaryIndex ( const QString & tablename ) const
QSqlRecord record ( const QString & tablename ) const
QSqlRecord record ( const QSqlQuery & query ) const
QSqlRecordInfo recordInfo ( const QString & tablename ) const
QSqlRecordInfo recordInfo ( const QSqlQuery & query ) const
QSqlQuery exec ( const QString & query = QString::null ) const
QSqlError lastError () const
bool transaction ()
bool commit ()
bool rollback ()
virtual void setDatabaseName ( const QString & name )
virtual void setUserName ( const QString & name )
virtual void setPassword ( const QString & password )
virtual void setHostName ( const QString & host )
virtual void setPort ( int p )
QString databaseName () const
QString userName () const
QString password () const
QString hostName () const
QString driverName () const
int port () const
QSqlDriver * driver () const

  Static Public Members
QSqlDatabase * addDatabase ( const QString & type, const QString & connectionName = defaultConnection )
QSqlDatabase * database ( const QString & connectionName = defaultConnection, bool open = TRUE )
void removeDatabase ( const QString & connectionName )
bool contains ( const QString & connectionName = defaultConnection )
QStringList drivers ()

  Properties
QString databaseName - the name of the database
QString hostName - the host name where the database resides
QString password - the password used to connect to the database
int port - the port used to connect to the database
QString userName - the user name connected to the database

  Protected Members
QSqlDatabase ( const QString & driver, const QString & name, QObject * parent = 0, const char * objname = 0 )

DESCRIPTION
The QSqlDatabase class is used to create SQL database connections and provide transaction handling.

This class is used to create connections to SQL databases. It also provides transaction handling functions for those database drivers that support transactions.

The QSqlDatabase class itself provides an abstract interface for accessing many types of database backend. Database-specific drivers are used internally to actually access and manipulate data, (see QSqlDriver). Result set objects provide the interface for executing and manipulating SQL queries (see QSqlQuery).

See also Database Classes.

MEMBER FUNCTION DOCUMENTATION

QSqlDatabase::QSqlDatabase ( const QString & driver, const QString & name, QObject * parent = 0, const char * objname = 0 ) [protected]
Creates a QSqlDatabase connection called name that uses the driver referred to by driver, with the parent parent and the object name objname. If the driver is not recognized, the database connection will have no functionality.

The currently available drivers are:

QODBC3 - ODBC (Open Database Connectivity) Driver

QOCI8 - Oracle Call Interface Driver

QPSQL7 - PostgreSQL v6.x and v7.x Driver

QTDS7 - Sybase Adaptive Server and Microsoft SQL Server Driver

QMYSQL3 - MySQL Driver

Note that additional 3<sup>rd</sup> party drivers can be loaded dynamically.

QSqlDatabase::~QSqlDatabase ()
Destroys the object and frees any allocated resources.

QSqlDatabase * QSqlDatabase::addDatabase ( const QString & type, const QString & connectionName = defaultConnection ) [static]
Adds a database to the list of database connections using the driver type and the connection name connectionName.

The database connection is referred to by connectionName. The newly added database connection is returned. This pointer is owned by QSqlDatabase and will be deleted on program exit or when removeDatabase() is called. If connectionName is not specified, the newly added database connection becomes the default database connection for the application, and subsequent calls to database() (without a database name parameter) will return a pointer to it.

See also database() and removeDatabase().

Examples:

void QSqlDatabase::close ()
Closes the database connection, freeing any resources acquired.

bool QSqlDatabase::commit ()
Commits a transaction to the database if the driver supports transactions. Returns TRUE if the operation succeeded; otherwise returns FALSE.

See also QSqlDriver::hasFeature() and rollback().

bool QSqlDatabase::contains ( const QString & connectionName = defaultConnection ) [static]
Returns TRUE if the list of database connections contains connectionName; otherwise returns FALSE.

QSqlDatabase * QSqlDatabase::database ( const QString & connectionName = defaultConnection, bool open = TRUE ) [static]
Returns the database connection called connectionName. The database connection must have been previously added with addDatabase(). If open is TRUE (the default) and the database connection is not already open it is opened now. If no connectionName is specified the default connection is used. If connectionName does not exist in the list of databases, 0 is returned. The pointer returned is owned by QSqlDatabase and should not be deleted.

Examples:

QString QSqlDatabase::databaseName () const
Returns the name of the database. See the "databaseName" property for details.

QSqlDriver * QSqlDatabase::driver () const
Returns the database driver used to access the database connection.

QString QSqlDatabase::driverName () const
Returns the name of the driver used by the database connection.

QStringList QSqlDatabase::drivers () [static]
Returns a list of all available database drivers.

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

    QStringList list = QSqlDatabase::drivers();
    QStringList::Iterator it = list.begin();
    while( it != list.end() ) {
        myProcessing( *it );
        ++it;
    }

QSqlQuery QSqlDatabase::exec ( const QString & query = QString::null ) const
Executes a SQL statement (e.g. an INSERT, UPDATE or DELETE statement) on the database, and returns a QSqlQuery object. Use lastError() to retrieve error information. If query is QString::null, an empty, invalid query is returned and lastError() is not affected.

See also QSqlQuery and lastError().

QString QSqlDatabase::hostName () const
Returns the host name where the database resides. See the "hostName" property for details.

bool QSqlDatabase::isOpen () const
Returns TRUE if the database connection is currently open; otherwise returns FALSE.

bool QSqlDatabase::isOpenError () const
Returns TRUE if there was an error opening the database connection; otherwise returns FALSE. Error information can be retrieved using the lastError() function.

QSqlError QSqlDatabase::lastError () const
Returns information about the last error that occurred on the database. See QSqlError for more information.

Examples:

bool QSqlDatabase::open ()
Opens the database connection using the current connection values. Returns TRUE on success; otherwise returns FALSE. Error information can be retrieved using the lastError() function.

See also lastError().

Examples:

bool QSqlDatabase::open ( const QString & user, const QString & password )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Opens the database connection using user name and password. Returns TRUE on success; otherwise returns FALSE. Error information can be retrieved using the lastError() function.

See also lastError().

QString QSqlDatabase::password () const
Returns the password used to connect to the database. See the "password" property for details.

int QSqlDatabase::port () const
Returns the port used to connect to the database. See the "port" property for details.

QSqlIndex QSqlDatabase::primaryIndex ( const QString & tablename ) const
Returns the primary index for table tablename. If no primary index exists an empty QSqlIndex will be returned.

QSqlRecord QSqlDatabase::record ( const QString & tablename ) const
Returns a QSqlRecord populated with the names of all the fields in the table (or view) named tablename. The order in which the fields are returned is undefined. If no such table (or view) exists, an empty record is returned.

See also recordInfo().

QSqlRecord QSqlDatabase::record ( const QSqlQuery & query ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns a QSqlRecord populated with the names of all the fields used in the SQL query. If the query is a "SELECT *" the order in which fields are returned is undefined.

See also recordInfo().

QSqlRecordInfo QSqlDatabase::recordInfo ( const QString & tablename ) const
Returns a QSqlRecordInfo populated with meta data about the table or view tablename. If no such table or view exists, an empty record is returned.

See also QSqlRecordInfo, QSqlFieldInfo, and record().

QSqlRecordInfo QSqlDatabase::recordInfo ( const QSqlQuery & query ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns a QSqlRecordInfo object with meta data for the QSqlQuery query. Note that this overloaded function may return less information than the recordInfo() function which takes the name of a table as parameter.

See also QSqlRecordInfo, QSqlFieldInfo, and record().

void QSqlDatabase::removeDatabase ( const QString & connectionName ) [static]
Removes the database connection connectionName from the list of database connections.

Warning: There should be no open queries on the database connection when this function is called, otherwise a resource leak will occur.

bool QSqlDatabase::rollback ()
Rolls a transaction back on the database if the driver supports transactions. Returns TRUE if the operation succeeded; otherwise returns FALSE.

See also QSqlDriver::hasFeature(), commit(), and transaction().

void QSqlDatabase::setDatabaseName ( const QString & name ) [virtual]
Sets the name of the database to name. See the "databaseName" property for details.

void QSqlDatabase::setHostName ( const QString & host ) [virtual]
Sets the host name where the database resides to host. See the "hostName" property for details.

void QSqlDatabase::setPassword ( const QString & password ) [virtual]
Sets the password used to connect to the database to password. See the "password" property for details.

void QSqlDatabase::setPort ( int p ) [virtual]
Sets the port used to connect to the database to p. See the "port" property for details.

void QSqlDatabase::setUserName ( const QString & name ) [virtual]
Sets the user name connected to the database to name. See the "userName" property for details.

QStringList QSqlDatabase::tables () const
Returns a list of tables in the database.

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

    QStringList list = myDatabase.tables();
    QStringList::Iterator it = list.begin();
    while( it != list.end() ) {
        myProcessing( *it );
        ++it;
    }

bool QSqlDatabase::transaction ()
Begins a transaction on the database if the driver supports transactions. Returns TRUE if the operation succeeded; otherwise returns FALSE.

See also QSqlDriver::hasFeature(), commit(), and rollback().

QString QSqlDatabase::userName () const
Returns the user name connected to the database. See the "userName" property for details.

  Property Documentation

QString databaseName
This property holds the name of the database.

Note that the database name is the TNS Service Name for the QOCI8 (Oracle) driver, and the DSN or DSN filename for the QODBC3 driver. If a DSN filename is used, the file have to have a .dsn extension.

There is no default value.

Set this property's value with setDatabaseName() and get this property's value with databaseName().

QString hostName
This property holds the host name where the database resides.

There is no default value.

Set this property's value with setHostName() and get this property's value with hostName().

QString password
This property holds the password used to connect to the database.

There is no default value.

Set this property's value with setPassword() and get this property's value with password().

int port
This property holds the port used to connect to the database.

There is no default value.

Set this property's value with setPort() and get this property's value with port().

QString userName
This property holds the user name connected to the database.

There is no default value.

Set this property's value with setUserName() and get this property's value with userName().

SEE ALSO
http://doc.trolltech.com/qsqldatabase.html http://www.trolltech.com/faq/tech.html

COPYRIGHT
Copyright 1992-2001 Trolltech AS, http://www.trolltech.com. See the license file included in the distribution for a complete license statement.

AUTHOR
Generated automatically from the source code.

BUGS
If you find a bug in Qt, please report it as described in http://doc.trolltech.com/bughowto.html. Good bug reports help us to help you. Thank you.

The definitive Qt documentation is provided in HTML format; it is located at $QTDIR/doc/html and can be read using Qt Assistant or with a web browser. This man page is provided as a convenience for those users who prefer man pages, although this format is not officially supported by Trolltech.

If you find errors in this manual page, please report them to qt-bugs@trolltech.com. Please include the name of the manual page (qsqldatabase.3) and the Qt version (3.1.2).