Database Connection Configuration Options

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## SQLite C Interface

## Database Connection Configuration Options

>     #define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
>     #define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
>     #define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */

These constants are the available integer configuration options that can be passed as the second argument to the sqlite3_db_config() interface.

New configuration options may be added in future releases of SQLite. Existing configuration options might be discontinued. Applications should check the return code from sqlite3_db_config() to make sure that the call worked. The sqlite3_db_config() interface will return a non-zero error code if a discontinued or unsupported configuration option is invoked.

SQLITE_DBCONFIG_LOOKASIDE
  This option takes three additional arguments that determine the lookaside memory allocator configuration for the database connection. The first argument (the third parameter to sqlite3_db_config() is a pointer to a memory buffer to use for lookaside memory. The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb may be NULL in which case SQLite will allocate the lookaside buffer itself using sqlite3_malloc(). The second argument is the size of each lookaside buffer slot. The third argument is the number of slots. The size of the buffer in the first argument must be greater than or equal to the product of the second and third arguments. The buffer must be aligned to an 8-byte boundary. If the second argument to SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally rounded down to the next smaller multiple of 8. The lookaside memory configuration for a database connection can only be changed when that connection is not currently using lookaside memory, or in other words when the "current value" returned by sqlite3_db_status(D,SQLITE_CONFIG_LOOKASIDE,...) is zero. Any attempt to change the lookaside memory configuration when lookaside memory is in use leaves the configuration unchanged and returns SQLITE_BUSY.

SQLITE_DBCONFIG_ENABLE_FKEY
  This option is used to enable or disable the enforcement of foreign key constraints. There should be two additional arguments. The first argument is an integer which is 0 to disable FK enforcement, positive to enable FK enforcement or negative to leave FK enforcement unchanged. The second parameter is a pointer to an integer into which is written 0 or 1 to indicate whether FK enforcement is off or on following this call. The second parameter may be a NULL pointer, in which case the FK enforcement setting is not reported back.

SQLITE_DBCONFIG_ENABLE_TRIGGER
  This option is used to enable or disable triggers. There should be two additional arguments. The first argument is an integer which is 0 to disable triggers, positive to enable triggers or negative to leave the setting unchanged. The second parameter is a pointer to an integer into which is written 0 or 1 to indicate whether triggers are disabled or enabled following this call. The second parameter may be a NULL pointer, in which case the trigger setting is not reported back.

See also lists of Objects, Constants, and Functions.