add support for custom delimiter in mysql migrations

[phemmer]

This implements a solution for #38

It basically adds support for the migration file including delimiter foo in the first line, and using foo as the delimiter for multiple statements.

Yes, this is a hack, but it solves the issue, and doesn't introduce new syntax (delimiter foo is valid for mysql CLI)

[mattes]

Thanks for your PR. Not sure if I got it right. DELIMITER just changes the ; symbol to something else. Could you give an example how that would work with multiple statements?

[phemmer]

This is one of our migrations which is using it:

delimiter "\n--\n"

CREATE TABLE session_event (
    id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    type ENUM('insert','update') NOT NULL,
    session_id BIGINT UNSIGNED NOT NULL
) engine=InnoDB

--

CREATE TRIGGER session_insert AFTER INSERT ON session
FOR EACH ROW
BEGIN
    INSERT INTO session_event SET type='insert', session_id=NEW.id;
    SET @event_id = LAST_INSERT_ID();
    SET @event_id_min = GREATEST(@event_id, 1000) - 1000;
    DELETE FROM session_event WHERE id < @event_id_min;
END

--

CREATE TRIGGER sesion_update AFTER UPDATE ON session
FOR EACH ROW
BEGIN
    INSERT INTO session_event SET type='update', session_id=NEW.id;
    SET @event_id = LAST_INSERT_ID();
    SET @event_id_min = GREATEST(@event_id, 1000) - 1000;
    DELETE FROM session_event WHERE id < @event_id_min;
END

[mattes]

I see. How about implementing https://github.com/ziutek/mymysql#example-4---multi-statement--multi-result ?

[phemmer]

I don't see how that is relevant. The issue isn't executing multiple statements, the issue is executing statements with a semicolon in them.

[mattes]

I think by implementing ziutek/mymysql we don't need any workarounds for delimiters.

[phemmer]

I don't think it'll have any bearing on the issue. The package might have better support for multiple SQL statements, but I still see no way to change the delimiter.

[phemmer]

Closing this since it seems to have gone stale. We've also switched to another migration tool which among other things, has support for custom statement delimiters.