Last night I attended a PerlMongers group meeting here in Oakland, CA and one of the presenters at the meeting asserted that MySQL could not claim to be a completely relational database because it doesn't let you define foreign keys. As a result, he feels that MySQL fails the ACID test (atomicity, consistency, referential integrity, and durability), and he advised people to avoid using it in Perl applications and instead use Postgres or some other relational database with more stability. He cited an example where you might have a one-to-one relationship between primary key values in two tables and if you deleted a value from one of the tables, MySQL would leave that value in the other table as dangling data without warning you to take care of it and as a result really mess up your database. Can anyone on the Koha list comment on this assertion and what the consequences might be for Koha? Larry Currie -- Lawrence W. Currie User Services Librarian California Academy of Sciences Golden Gate Park San Francisco, CA 94118 lcurrie@calacademy.org (415) 750-7108 (415) 750-7106 fax http://www.calacademy.org/research/library/