transaction on Memory engine?

[Martín Colodrero]

Hello guy, finally i'm use MySql just like session server, perhaps isn't a good idea, but can't find other good session server, MCache is not what I am looking for.

Anyway, i'm create a MySql function that create a session id and save into a Memory table, the problem is becouse i'm need to check if exists this value or not and then insert.

The question is how? i'm reading about SELECT .. FOR UPDATE, INSERT ... ON DUPLICATE KEY..., but nothing.

What can i do to check that?

Thank in advance.