Each entry in most SQLite tables (except for WITHOUT ROWID tables) has a unique 64-bit signed integer key called the "rowid". The rowid is always available as an undeclared column named ROWID, OID, or _ROWID_ as long as those names are not also used by explicitly declared columns. If the table has a column of type INTEGER PRIMARY KEY then that column is another alias for the rowid.
The sqlite3_last_insert_rowid(D) interface usually returns the rowid of the most recent successful INSERT into a rowid table or virtual table on database connection D. Inserts into WITHOUT ROWID tables are not recorded. If no successful INSERTs into rowid tables have ever occurred on the database connection D, then sqlite3_last_insert_rowid(D) returns zero.
As well as being set automatically as rows are inserted into database tables, the value returned by this function may be set explicitly by sqlite3_set_last_insert_rowid()
Some virtual table implementations may INSERT rows into rowid tables as part of committing a transaction (e.g. to flush data accumulated in memory to disk). In this case subsequent calls to this function return the rowid associated with these internal INSERT operations, which leads to unintuitive results. Virtual table implementations that do write to rowid tables in this way can avoid this problem by restoring the original rowid value using sqlite3_set_last_insert_rowid() before returning control to the user.
If an INSERT occurs within a trigger then this routine will return the rowid of the inserted row as long as the trigger is running. Once the trigger program ends, the value returned by this routine reverts to what it was before the trigger was fired.
An INSERT that fails due to a constraint violation is not a successful INSERT and does not change the value returned by this routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, and INSERT OR ABORT make no changes to the return value of this routine when their insertion fails. When INSERT OR REPLACE encounters a constraint violation, it does not fail. The INSERT continues to completion after deleting rows that caused the constraint problem so INSERT OR REPLACE will always change the return value of this interface.
For the purposes of this routine, an INSERT is considered to be successful even if it is subsequently rolled back.
This function is accessible to SQL statements via the last_insert_rowid() SQL function.
If a separate thread performs a new INSERT on the same database connection while the sqlite3_last_insert_rowid() function is running and thus changes the last insert rowid, then the value returned by sqlite3_last_insert_rowid() is unpredictable and might not equal either the old or the new last insert rowid.
SQLite is in the Public Domain.