sqlite3_db_handle —
Find The Database Handle Of A Prepared Statement
sqlite3 *
sqlite3_db_handle(sqlite3_stmt*);
The sqlite3_db_handle interface returns the database connection handle to which
  a prepared statement belongs. The database connection returned by
  sqlite3_db_handle is the same database connection that was the first argument
  to the sqlite3_prepare_v2() call (or its variants) that was used to create the
  statement in the first place.