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Diffstat (limited to 'doc/src/snippets/code/src_sql_kernel_qsqldatabase.cpp')
-rw-r--r-- | doc/src/snippets/code/src_sql_kernel_qsqldatabase.cpp | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/doc/src/snippets/code/src_sql_kernel_qsqldatabase.cpp b/doc/src/snippets/code/src_sql_kernel_qsqldatabase.cpp new file mode 100644 index 0000000000..50ea67c104 --- /dev/null +++ b/doc/src/snippets/code/src_sql_kernel_qsqldatabase.cpp @@ -0,0 +1,135 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** $QT_END_LICENSE$ +** +****************************************************************************/ + +//! [0] +// WRONG +QSqlDatabase db = QSqlDatabase::database("sales"); +QSqlQuery query("SELECT NAME, DOB FROM EMPLOYEES", db); +QSqlDatabase::removeDatabase("sales"); // will output a warning + +// "db" is now a dangling invalid database connection, +// "query" contains an invalid result set +//! [0] + + +//! [1] +{ + QSqlDatabase db = QSqlDatabase::database("sales"); + QSqlQuery query("SELECT NAME, DOB FROM EMPLOYEES", db); +} +// Both "db" and "query" are destroyed because they are out of scope +QSqlDatabase::removeDatabase("sales"); // correct +//! [1] + + +//! [2] +QSqlDatabase::registerSqlDriver("MYDRIVER", + new QSqlDriverCreator<MyDatabaseDriver>); +QSqlDatabase db = QSqlDatabase::addDatabase("MYDRIVER"); +//! [2] + + +//! [3] +... +db = QSqlDatabase::addDatabase("QODBC"); +db.setDatabaseName("DRIVER={Microsoft Access Driver (*.mdb)};FIL={MS Access};DBQ=myaccessfile.mdb"); +if (db.open()) { + // success! +} +... +//! [3] + + +//! [4] +... +// MySQL connection +db.setConnectOptions("CLIENT_SSL=1;CLIENT_IGNORE_SPACE=1"); // 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 + ... +} +//! [4] + + +//! [5] +#include "qtdir/src/sql/drivers/psql/qsql_psql.cpp" +//! [5] + + +//! [6] +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 query; +query.exec("SELECT NAME, ID FROM STAFF"); +... +//! [6] + + +//! [7] +unix:LIBS += -lpq +win32:LIBS += libpqdll.lib +//! [7] + + +//! [8] +QSqlDatabase db; +qDebug() << db.isValid(); // Returns false + +db = QSqlDatabase::database("sales"); +qDebug() << db.isValid(); // Returns true if "sales" connection exists + +QSqlDatabase::removeDatabase("sales"); +qDebug() << db.isValid(); // Returns false +//! [8] |