On 1 Jun 2011, at 7:12pm, Jan Hudec wrote: > On Wed, Jun 01, 2011 at 10:17:02 -0400, Pavel Ivanov wrote: >>> From within a BEGIN TRANSACTION and END TRANSACTION block, should I not >>> update the same row in a table more than once? >> >> You can update it as many times as you need. >> >>> What are the exact limitations on what I can do during a Transaction? >> >> Do not update a table if there is some select statement currently > > Actually insert, update and delete are OK. Drop and alter table are > a problem.
Pavel is right. He left out some details to make things simple. Suppose you do a SELECT ... WHERE ... that returns ten rows. You retrieve three rows, then make a change that would mean you should have retrieved eleven rows, not ten. You can't predict what SQLite will do without knowing the internal workings of SQLite, right ? So don't do that. The same is true even if the only thing you change is values to be returned. Does SQLite copy the all values when you execute the SELECT, or row-by-row as you step through the results ? Again, you don't know unless you know the internal workings of SQLite. So don't do that. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
