Once again, this varies form db to db. Even sqlite3 can now allow readers while the db is locked by setting the Write Ahead Locking pragma.
For mySQL, there is a LOCK and an UNLOCK command which allow you to lock individual tables for read and/or write access, as well as BEGIN and END, which lock the whole database. There's a discussion on how LOCK/UNLOCK and BEGIN/END work here<http://dev.mysql.com/doc/refman/5.5/en/lock-tables-and-transactions.html> but I'd be inclined to use LOCK and UNLOCK rather than BEGIN/END for more granularity unless you are carrying out some admin task for which you need exclusive access to the whole db. I don't know anything about locking on other SQL implementations (yet!). Pete lcSQL Software <http://www.lcsql.com> On Thu, Apr 26, 2012 at 3:22 PM, Bob Sneidar <[email protected]> wrote: > Oh thanks. I was aware that beginning a transaction made the database > writable by only the client who began the transaction, but does it lock > people out of reads as well? In the past I would manually lock a database > while inserting records or before doing a transactional update, so that I > could mark a particular master record as read only. I would then unlock the > database and update as necessary to minimize the impact on other users. I > did this only because that was what an old app called SBT written in Foxpro > used to do, and that was all I knew at the time, but with transactions, > maybe I don't need to worry about that anymore. > > Bob > > > On Apr 26, 2012, at 3:14 PM, Peter Haworth wrote: > > > I think you're using mySQL Bob? If so, be aware that BEGIN and END are > > also the means by which you lock the database. Doesn't matter too much > > with sqlite because it's basically a single user db but with multi user > dbs > > like mySQL (actually just about any db other than sqlite), locking is a > > whole other story! > > > > Pete > > lcSQL Software <http://www.lcsql.com> > > > > > > > > On Thu, Apr 26, 2012 at 2:58 PM, Bob Sneidar <[email protected]> wrote: > > > >> Yes, transactions... good! I need to incorporate them into my app when I > >> am ready to go into production (as if I will ever get to that point!). > >> > >> Bob > >> > >> > >> On Apr 26, 2012, at 2:38 PM, Terry Judd wrote: > >> > >>> Wow, thanks Pete - I'll definitely give this method a try. > >>> > >>> Terry.. > >> > >> > >> _______________________________________________ > >> use-livecode mailing list > >> [email protected] > >> Please visit this url to subscribe, unsubscribe and manage your > >> subscription preferences: > >> http://lists.runrev.com/mailman/listinfo/use-livecode > >> > > _______________________________________________ > > use-livecode mailing list > > [email protected] > > Please visit this url to subscribe, unsubscribe and manage your > subscription preferences: > > http://lists.runrev.com/mailman/listinfo/use-livecode > > > _______________________________________________ > use-livecode mailing list > [email protected] > Please visit this url to subscribe, unsubscribe and manage your > subscription preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode > _______________________________________________ use-livecode mailing list [email protected] Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
