On Thu, Dec 1, 2011 at 6:17 AM, Ludo Brands <ludo.bra...@free.fr> wrote: > >> I can't keep a transaction (server locked) all the time. >> > > What database are you using that locks up the server when a transaction is > started?
MS SQLServer 2008. Lock the registers, not the server... sorry. > Oracle for example starts an transaction as soon as you send an executable > SQL Statement. Opening a connection starts a transaction on the server. > Therefor it is important to match this behavior on the client side and force > the use of a TSQLTransaction. Using TADOConnection doesn't change this. ADO > is just hiding it from you. Ok, I can accept the TADOConnection can hiding a lot of things from me, but I think it do open many transactions all the time. Using SQLServer Profiler, I can see all SQL that are executing on the server. So, I do not see BEGIN TRAN all the time, just when I call BeginTrans. > As long as you use a transaction level that is lower or equal to Read > committed, a transaction is almost at no cost to a database server (other > than access that doesn't support transactions or mysql that uses a different > backend to support transactions). I'm a tester of the new connector TMSSQLServer to SQLdb, by LacaK: http://lazarus.freepascal.org/index.php/topic,15135.msg80922.html#msg80922 If the component Open a Query I see BEGIN TRAN and... the transaction isn't closed! Well, maybe there is a bug in the new class by I see the SQLdb implementation and that class follow the design. What I know is: "if a transaction is open, it's should be closed as fast you can"... but if you right, the phrase should be " "if a transaction is open, it's should be closed as fast you can, IF you update something". Is that correct to you? > In a client server application, datasets are local copies of (a part of) the > database and should be short lived for tables that are updated regularly. > Re-opening (re-fetching) data from such tables after a commit or rollback is > almost a must to avoid the client working with old/wrong data. If you have > datasets linked to "low or no update" tables, attach them to a different > connection. Ok, but I shoud be the controller of my DataSets, shouldn't it? If, eg., I use RAD, how can I controller the DataSets that are using for the users in DBGrid or something, if all DataSets will be closed if he update something (that need a transaction)? Marcos Douglas _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
