Question

I think in PostgreSQL you can use a function to generate your primary key in a table instead of just using auto_increment. Something similar to:

CREATE TABLE `blah` (
    `id` bigint(20) unsigned NOT NULL my_generator_function(),
    etc.

Where my_generator_function() would return a bigint.

Is that possible with MySQL or do I have to do that from the application code myself?

Answer 1

You can create a trigger –

CREATE TRIGGER trigger1
  BEFORE INSERT
  ON table1
  FOR EACH ROW
BEGIN
  IF NEW.id = 0 THEN -- generate new ID if zero is set
    SET NEW.id = ...; -- write your code to generate new ID
  END IF;
END