Re: DELETE with LIMIT (or my first hack)

its pretty clear to me that's 2 different needs here, both linked to DELETE/UPDATE behavior.

A) an feature MySQL-like which will DELETE/UPDATE just K tuples
B) an feature to protect the database in case the DBA forget the "WHERE" statement

I think that the first feature its pretty reasonable for many reasons - some of then listed below (not in order of importance):
 1) MySql compatibility: will turn more easy intercompatibility
 2) speed: why scan all the table if its expected to affect just one row ?
 3) possibility to batch operation (paginate UPDATE/DELETE)
 4) easy-to-use in some operations (like delete the row with higher Y field): its necessary to implement with "ORDER BY"
 5) some others independent (and possibly weird needs) things that i forget

The second feature its something to turn the PostgreSQL more secure: in others words armor from DBA. The syntax maybe will something like "DELETE .... ASSERT 1", or an explicit keyword for this, like: "DELETEO ...". So, the mechanism should be give an error and rollback if the command affect more than specified tuples. IMHO this its a very weird syntax and so much non-standard SQL. So I believe this not a so-necessary feature. Ok I known that I started this discussion (around this weird feature, not the first and reasonable feature), but was good to instigate others thoughts.

Sds,
--
Daniel Loureiro