All other trademarks are property of their respective owners. Qt and respective logos are trademarks of The Qt Company Ltd. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Transactions can be used to ensure that a complex operation is atomic (for example, looking up a foreign key and creating a record), or to provide a means of canceling a complex change in the middle.Ĭonnecting to Databases Using the SQL Model Classesĭocumentation contributions included herein are the copyrights of exec( "INSERT INTO project (id, name, ownerid) " "VALUES (201, 'Manhattan Project', " + QString ::number(employeeId) + ')') exec( "SELECT id FROM employee WHERE name = 'Torild Halvorsen'") In the following example, we call QSqlQuery::size() to determine the size of a result set of the underlying database supports that feature otherwise, we navigate to the last record and use the query's position to tell us how many records there are. To determine whether a database driver supports a given feature, use QSqlDriver::hasFeature(). The current row index is returned by QSqlQuery::at(), and the total number of rows in the result set is available as QSqlQuery::size() for databases that support it. You can navigate within the dataset using QSqlQuery::next(), QSqlQuery::previous(), QSqlQuery::first(), QSqlQuery::last(), and QSqlQuery::seek(). In the code snippet, we call QVariant::toString() and QVariant::toInt() to convert variants to QString and int.įor an overview of the recommended types for use with Qt-supported Databases, please refer to this table. ![]() The different database types are automatically mapped into the closest Qt equivalent. QSqlQuery::value() returns a QVariant, a type that can hold various C++ and core Qt data types such as int, QString, and QByteArray. ![]() Fields are specified as zero-based indexes. The QSqlQuery::value() function returns the value of a field in the current record. Congratulations now so that Qt Creator recognize them, put them at C:QtQt5.2.0ToolsQtCreatorbinpluginssqldrivers, and put it in the bin directory.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |