On 02/12/11 14:02, Gavin Mitchell wrote:
> But if the data is changed within the table itself or a form based on
> the table or query it starts a transaction and adds all available fields
> into the where clause
>
> 2011-12-01 10:03:52 GMT LOG: statement: BEGIN;UPDATE
> "ua"."pole_survey_tbl" SET "completedby"=E'test' WHERE "pole_survey_id"
> = 6478 AND "survey_id" = 1025 and (etc…….)
>
> I chopped the log entry short but there are AND entries fo all fields in
> the table
It's an implementation of "optimistic locking". Imagine we are both
updating the same row at the same time. If my update gets committed
before yours, then yours won't find a row to update. Otherwise my
changes could be overwritten without you knowing.
--
Richard Huxton
Archonet Ltd