Sqlite - insert into multiple tables with an auto-increment PID - sqlite

Question

I'm using SQLite. I have two tables:
Log:
pid INTEGER PRIMARY KEY AUTOINCREMENT
action INTEGER NOT NULL
.... ect.
ErrorExtras:
pid INTEGER REFERENCES log(pid)
msg TEXT,
request TEXT
Now when an error occurs, I want to insert into both. Inserting into Log is easy, as it generates the PID, however, inserting into ErrorExtras is harder since I don't know the PID without doing a query. If I insert into Log, query for the PID and then insert into ErrorExtras, that seems quie messy. Is there some kind of shortcut for these kinds of inserts?
In my case, this is possible because the other info in log uniquely identifies the pid (so there's a combined key), but what if this weren't the case?

Answer 1

You needn't query for the insert_id, just use the last_insert_id in the select statement in ErrorExtras and Bob's your uncle.

Answer 2

If you have control of your SQL commands, you can use the last_insert_rowid SQL function like this:
INSERT INTO Log(action) VALUES(42);
INSERT INTO ErrorExtras(pid, msg) VALUES(last_insert_rowid(), 'x');
(But this works only for the very next INSERT command, because afterwards, last_insert_rowid() returns the rowid of the ErrorExtras record.)
If you are using the C API, you can use the sqlite3_last_insert_rowid function:
sqlite3_prepare_v2(db, "INSERT INTO Log(action) VALUES(42)", -1, &stmt, NULL);
sqlite3_step(stmt);
sqlite3_finalize(stmt);
sqlite3_prepare_v2(db, "INSERT INTO ErrorExtras(pid,msg) VALUES(?,?)", -1, &stmt, NULL);
sqlite3_bind_int64(stmt, 1, sqlite3_last_insert_rowid(db));
sqlite3_bind_text(stmt, 2, "x", -1, SQLITE_TRANSIENT);
sqlite3_step(stmt);
sqlite3_finalize(stmt);
The APIs of other languages typically also have some mechanism to get the last inserted rowid.
For example, in Android, the insert function returns it:
ContentValues cv = new ContentValues();
cv.put("action", 42);
long log_rowid = db.insert("Log", null, cv);
ContentValues cv = new ContentValues();
cv.put("pid", log_rowid);
cv.put("msg", "x");
db.insert("ErrorExtras", null, cv);