On 6/1/2011 1:23 PM, Simon Slavin wrote: > 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. > _______________________________________________
Actually, you do know what SQLite does without knowing the internals. It claims to be serializable and ACID (http://www.sqlite.org/transactional.html), therefore it's fine. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
