CODEWITHSUNDEEP
sqlsqlite
mikesol
mikesol

Reputation: 1197

sqlite, triggers and concurrency

I am developing an application that uses an SQLite trigger that is in the form

CREATE TRIGGER bar_to_foo AFTER INSERT ON bar
  BEGIN
    DELETE * FROM foo;
    INSERT INTO foo SELECT FROM bar;
  END;

Multiple users will be using the application at the same time and potentially inserting into bar at the same time.

My question is: is there a chance that the triggers will execute in parallel? If so, the two deletes may happen before the inserts, which would result in a foo that contains bar twice over. This is not what I want - ideally, I'd the entirety of the trigger to execute before it reruns. If this is not default behavior in sqlite, is there a way to specify that this should happen?

Upvotes: 1

Views: 302

Answers (1)

CL.
CL.

Reputation: 180070

SQLite properly serializes all transactions. (And when you are not using explicit transaction, each top-level statement will be wrapped in an automatic transaction.)

No two transactions can write to the same database at the same time, whether from inside a trigger or in any other way.

Upvotes: 2

Related Questions