PRAGMA is a directive in SQL, particularly in SQLite, that is used to modify the operation of the SQLite library or to query the database for specific information. It allows users to set various parameters and configurations for the database environment, such as enabling or disabling certain features, setting performance-related options, or retrieving metadata about the database.
Some common uses of PRAGMA include:
- Setting the journal mode:
PRAGMA journal_mode = WAL;to enable Write-Ahead Logging. - Checking the database integrity:
PRAGMA integrity_check;to verify the integrity of the database. - Configuring foreign key support:
PRAGMA foreign_keys = ON;to enable foreign key constraints.
Overall, PRAGMA provides a way to interact with and configure the SQLite database engine beyond standard SQL commands.
