Sqlite Foreign Keys
According to the docs:
Assuming the library is compiled with foreign key constraints enabled, it must still be enabled by the application at runtime, using the PRAGMA foreign_keys command. For example:
sqlite> PRAGMA foreign_keys = ON;
Foreign key constraints are disabled by default (for backwards compatibility), so must be enabled separately for each database connection separately.
So, after your sqlite3_open(), you probably want to add the following:
sqlite3_exec(ppDb, "PRAGMA foreign_keys = ON;", 0, 0, 0);
I had difficulties with enabling foreign keys using HDBC-sqlite3 API because mentioned PRAGMA required to be invoked beyond transaction and the library opens in background a new transaction after connection gets established and after each commit. Still the workaround was easy:
main = do conn <- connectSqlite3 "test.db" runRaw conn "COMMIT; PRAGMA foreign_keys = ON; BEGIN TRANSACTION"