QtSql

QtSql is a module of the Qt application framework that provides an abstraction layer for accessing SQL databases. It offers a driver-based API that allows applications to connect to relational databases using SQL without writing database-specific code. The module supports a range of database backends through drivers, such as SQLite, MySQL, PostgreSQL, Oracle, and ODBC, via a plugin system. The core components include QSqlDatabase, which represents a connection; QSqlQuery, which executes SQL statements and supports prepared statements; QSqlQueryModel and QSqlTableModel for populating views with result data; and QSqlRelationalTableModel for relational data. The driver abstraction is exposed by QSqlDriver, which defines capabilities and error reporting via QSqlError. The module also provides inspection primitives such as QSqlRecord and QSqlField to examine result schemas.

In typical use, an application loads a suitable driver with QSqlDatabase::addDatabase, sets the connection parameters (host, database name, user, password), and opens the connection. SQL statements can be executed through QSqlQuery, with results accessed via bindings or by iterating records. The model classes enable binding database results directly to Qt views, while transactions and error handling are supported through QSqlQuery and QSqlError. Developers should prefer per-connection usage and respect thread-safety guidelines, as QSqlDatabase connections are typically not shared across threads.

QtSql is designed to integrate with Qt's model-view architecture, enabling seamless data presentation and editing in widgets. Its functionality is expanded with database-specific features provided by the underlying drivers, which may affect SQL dialect and behavior.