On 22/02/07, Shashank Tripathi <shanx@xxxxxxxxx> wrote:
> I would do a CHECK (trim(a) <> '') TRIM() would add some processing time, so I'd include it only if there was a chance of spaces getting added. From a puritanical point of view, it is definitely a good idea. To the original poster, this syntax should work in MySQL as well: create table mytable (mycol text not null check (mycol <> '')); Problem is, if you created your table before MySQL 5, and now simply want to ALTER your table (which is what I gather you wish to do, as you already have the table) then adding the CHECK condition may not work. I cannot help in this case, and from the turn this thread has taken, not many others I suppose. Why not try a MySQL experts list instead of PostgreSQL, but be prepared to have to recreate the table in MySQL 5 with the CHECK constraint, and then importing your data in to it. Good luck!
Sorry, I spoke too soon. MySQL does not do the constraints jig yet. "The CHECK clause is parsed but ignored by all storage engines." - From http://dev.mysql.com/doc/refman/5.0/en/create-table.html So you may want to adopt some kludges, such as updatable views: http://arjen-lentz.livejournal.com/49881.html If I were you, I'd just stick to error-checking in the application layer for now, or consider slowly switching to PostgreSQL. (No plug intended) Shanx
