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QSqlDatabase(3qt)								QSqlDatabase(3qt)

NAME
       QSqlDatabase - Used to create SQL database connections and to 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
       QStringList tables ( QSql::TableType type ) 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 )
       void setConnectOptions ( const QString & options = QString::null )
       QString databaseName () const
       QString userName () const
       QString password () const
       QString hostName () const
       QString driverName () const
       int port () const
       QString connectOptions () const
       QSqlDriver * driver () const

   Static Public Members
       QSqlDatabase * addDatabase ( const QString & type, const QString & connectionName =
	   defaultConnection )
       QSqlDatabase * addDatabase ( QSqlDriver * driver, const QString & connectionName =
	   defaultConnection )
       QSqlDatabase * database ( const QString & connectionName = defaultConnection, bool open =
	   TRUE )
       void removeDatabase ( const QString & connectionName )
       void removeDatabase ( QSqlDatabase * db )
       bool contains ( const QString & connectionName = defaultConnection )
       QStringList drivers ()
       void registerSqlDriver ( const QString & name, const QSqlDriverCreatorBase * creator )
       bool isDriverAvailable ( const QString & name )

   Properties
       QString connectOptions - the database connect options
       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 & type, const QString & name, QObject * parent = 0, const
	   char * objname = 0 )
       QSqlDatabase ( QSqlDriver * driver, QObject * parent = 0, const char * objname = 0 )

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

       Note that transaction handling is not supported by every SQL database. You can find out
       whether transactions are supported using QSqlDriver::hasFeature().

       The QSqlDatabase class provides an abstract interface for accessing many types of database
       backends. 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 & type, const QString & name, QObject * parent = 0,
       const char * objname = 0 ) [protected]
       Creates a QSqlDatabase connection called name that uses the driver referred to by type,
       with the parent parent and the object name objname. If the type is not recognized, the
       database connection will have no functionality.

       The currently available drivers are:

       <center>.nf

       </center>

       Additional third party drivers, including your own custom drivers, can be loaded
       dynamically.

       See also registerSqlDriver().

QSqlDatabase::QSqlDatabase ( QSqlDriver * driver, QObject * parent = 0, const char * objname = 0
       ) [protected]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Creates a database connection using the driver driver, with the parent parent and the
       object name objname.

       Warning: The framework takes ownership of the driver pointer, so it should not be deleted.

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. If connectionName is
       given, use database(connectionName) to retrieve a pointer to the database connection.

       Warning: If you add a database with the same name as an existing database, the new
       database will replace the old one. This will happen automatically if you call this
       function more than once without specifying connectionName.

       See also database() and removeDatabase().

       Examples:

QSqlDatabase * QSqlDatabase::addDatabase ( QSqlDriver * driver, const QString & connectionName =
       defaultConnection ) [static]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       This function is useful if you need to set up the database connection and instantiate the
       driver yourself. If you do this, it is recommended that you include the driver code in
       your own application. For example, setting up a custom PostgreSQL connection and
       instantiating the QPSQL7 driver can be done the following way:

	   #include "qtdir/src/sql/drivers/psql/qsql_psql.cpp"
       (We assume that qtdir is the directory where Qt is installed.) This will pull in the code
       that is needed to use the PostgreSQL client library and to instantiate a QPSQLDriver
       object, assuming that you have the PostgreSQL headers somewhere in your include search
       path.

	   PGconn* con = PQconnectdb( "host=server user=bart password=simpson dbname=springfield" );
	   QPSQLDriver* drv =  new QPSQLDriver( con );
	   QSqlDatabase* db = QSqlDatabase::addDatabase( drv ); // becomes the new default connection
	   QSqlQuery q;
	   q.exec( "SELECT * FROM people" );
	   ...

       The above code sets up a PostgreSQL connection and instantiates a QPSQLDriver object.
       Next, addDatabase() is called to add the connection to the known connections so that it
       can be used by the Qt SQL classes. When a driver is instantiated with a connection handle
       (or set of handles), Qt assumes that you have already opened the database connection.

       Remember that you must link your application against the database client library as well.
       The simplest way to do this is to add lines like those below to your .pro file:

	   unix:LIBS += -lpq
	   win32:LIBS += libpqdll.lib

       You will need to have the client library in your linker's search path.

       The method described above will work for all the drivers, the only difference is the
       arguments the driver constructors take. Below is an overview of the drivers and their
       constructor arguments.

       <center>.nf

       </center>

       Note: The host name (or service name) is needed when constructing the QTDSDriver for
       creating new connections for internal queries. This is to prevent the simultaneous usage
       of several QSqlQuery/QSqlCursor objects from blocking each other.

       Warning: The SQL framework takes ownership of the driver pointer, and it should not be
       deleted. The returned QSqlDatabase object is owned by the framework and must not be
       deleted. If you want to explicitly remove the connection, use removeDatabase()

       See also drivers().

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

       See also removeDatabase().

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().

QString QSqlDatabase::connectOptions () const
       Returns the database connect options. See the "connectOptions" property for details.

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.

       Warning: There are restrictions on the use of database connections in threaded
       applications. Please see the Thread Support in Qt document for more information about
       threading and SQL databases.

       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 the 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::isDriverAvailable ( const QString & name ) [static]
       Returns TRUE if a driver called name is available; otherwise returns FALSE.

       See also drivers().

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

       This function does not store the password it is given. Instead, the password is passed
       directly to the driver for opening a connection and is then discarded.

       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)
       called tablename. The order in which the fields appear in the record 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 appear in the record 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::registerSqlDriver ( const QString & name, const QSqlDriverCreatorBase *
       creator ) [static]
       This function registers a new SQL driver called name, within the SQL framework. This is
       useful if you have a custom SQL driver and don't want to compile it as a plugin.

       Example usage:

	   QSqlDatabase::registerSqlDriver( "MYDRIVER", new QSqlDriverCreator<MyDatabaseDriver> );
	   QSqlDatabase* db = QSqlDatabase::addDatabase( "MYDRIVER" );
	   ...

       Warning: The framework takes ownership of the creator pointer, so it should not be
       deleted.

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.

void QSqlDatabase::removeDatabase ( QSqlDatabase * db ) [static]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Removes the database connection db from the list of database connections. The QSqlDatabase
       object is destroyed when it is removed from the list.

       Warning: The db pointer is not valid after this function has been called. 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::setConnectOptions ( const QString & options = QString::null )
       Sets the database connect options to options. See the "connectOptions" property for
       details.

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 ( QSql::TableType type ) const
       Returns a list of the database's tables, system tables and views, as specified by the
       parameter type.

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

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

       Example: sql/sqltable/main.cpp.

QStringList QSqlDatabase::tables () const
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Returns a list of the database's tables that are visible to the user. To include views or
       system tables, use the version of this function that takes a table type parameter.

       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 connectOptions
       This property holds the database connect options.

       The format of the options string is a semi-colon separated list of option names or option
       = value pairs. The options depend on the database client used:

       <center>.nf

       </center>

       Example of usage:

	   ...
	   // MySQL connection
	   db->setConnectOptions( "CLIENT_SSL;CLIENT_IGNORE_SPACE" ); // use an SSL connection to the server
	   if ( !db->open() ) {
	       db->setConnectOptions(); // clears the connect option string
	       ...
	   }
	   ...
	   // PostgreSQL connection
	   db->setConnectOptions( "requiressl=1" ); // enable PostgreSQL SSL connections
	   if ( !db->open() ) {
	       db->setConnectOptions(); // clear options
	       ...
	   }
	   ...
	   // ODBC connection
	   db->setConnectOptions( "SQL_ATTR_ACCESS_MODE=SQL_MODE_READ_ONLY;SQL_ATTR_TRACE=SQL_OPT_TRACE_ON" ); // set ODBC options
	   if ( !db->open() ) {
	       db->setConnectOptions(); // don't try to set this option
	       ...
	   }

       Please refer to the client library documentation for more information about the different
       options. The options will be set prior to opening the database connection. Setting new
       options without re-opening the connection does nothing.

       See also

       Set this property's value with setConnectOptions() and get this property's value with
       connectOptions().

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.

       For the QODBC3 driver it can either be a DSN, a DSN filename (the file must have a .dsn
       extension), or a connection string. MS Access users can for example use the following
       connection string to open a .mdb file directly, instead of having to create a DSN entry in
       the ODBC manager:

	   ...
	   db = QSqlDatabase::addDatabase( "QODBC3" );
	   db->setDatabaseName( "DRIVER={Microsoft Access Driver (*.mdb)};FIL={MS Access};DBQ=myaccessfile.mdb" );
	   if ( db->open() ) {
	       // success!
	   }
	   ...
       ("FIL" is the required spelling in Microsoft's API.)

       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.

       Warning: This function stores the password in plain text within Qt. Use the open() call
       that takes a password as parameter to avoid this behaviour.

       See also open().

       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 1992-2007 Trolltech ASA, 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.3qt) and the Qt version (3.3.8).

Trolltech AS				 2 February 2007			QSqlDatabase(3qt)
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