thanks for your response, reenen... it does tend to make sense on the one hand but on the other i "must" ask if you have looked at and/or run the demo code i pointed to?
it does check if the connection is open ;) procedure TFormTryMySQL.ConnectButtonClick(Sender: TObject); begin // Check if we have an active connection. If so, let's close it. if MySQLConnection1.Connected then begin SQLTransaction1.Active := False; MySQLConnection1.Close; end; blahfooblah...; when i place logging lines in the above, the last logging line that executes is the one right above "MySQLConnection1.Close;" which indicates the error in is the "MySQLConnection1.Close;" library code... i can see where what you are saying may be possible but it doesn't make sense because the next time the above is executed, it works "properly" (ie: there's no error).. what it almost sounds like is that in closing the connection object, something was not created during the open which somehow does get created during the close... again, i dunno and that's why i'm here... one would think that demo code should work and work properly (ie: without error) out of the box... i won't point back to my comment about having problems with several other of the wiki demo apps not working for some reason or another :? Reenen Laurie wrote: > I am very uninformed when it comes to databases, but access violations > happens when you do stuff to stuff that's not there. > > My guess is that for some reason your "close" code gets fired twice, and > thus it's already closed by the time you get there the second time. > > So if there's a way to check if it's open, before you close it, I'd > suggest try to close it inside an if open... > > Regards, > -Reenen > > On Sun, Jan 18, 2009 at 9:39 PM, waldo kitty <wkitt...@windstream.net > <mailto:wkitt...@windstream.net>> wrote: > > > history: i'm a long time pascal coder... since TP3 first appeared on the > market... then to TP5 and most of my time with TP6/BP6 and numerous > commercial > apps under my belt... i've dabbled with OOP stuffs, TP7/BP7 and even > have a copy > of delphi6-personal that i've not been able to wrap my head > around... since my > delphi was a downloaded copy from Inprise, it is also a bit harder > to work with > since i've no real documentation that i can lay in my lap to look > over while > working on code :? :( > > in any case, i've been fighting a battle with mysql50conn for a few > weeks, > now... i started with Lazaruz 0.9.26 and last night installed > Lazarus 0.9.27 to > see if the problem i'm facing may have been fixed in there but it > has not and > i'm not even certain if the problem is in the library code or > possibly something > on this old win98SE box :? > > ok, enough of the history and story telling... > > the details: with the tutorial DB code on the wiki (yeah, i was > /finally/ able > to get two or three of those working after some starts, stops and > fits :P), > there's several that check to see if the connection to the database > is active > and if it is, they attempt to close it... my problem is that the > first attempt > to close the connection _always_ throws an error... i don't know > what specific > error code because the popup box doesn't state it... the box only says > > Access violation. > > Press Ok to ignore and risk data corruption. > Press Cancel to kill the program. > > [OK] [Cancel] > > i'm triggering my initial connection to the database via a button. i > click the > button, the connection takes place, data is retrieved, and the > connection is > attempted to close... that's when the error is thrown... however, if > i hit the > [OK] button to ignore the error then i can open and close the > connection to the > database with no problems... at least it appears that way because > other routines > gather other data from other tables and they all connect, gather, > and disconnect > without problems... all routines use the very same disconnect > routine and this > is what leads be to believe that there's something in the library > code that's > the problem... > > currently, all the code i'm using simply uses the close procedure of the > connection object (ie: MySQL50Connection.Close)... i've only one > graphical demo > app that doesn't exhibit this problem but it is using mysql4 in the > uses and a > lot of manual code instead of the connector, transaction, and sqlquery > objects... i also have the text modedemo app working and it doesn't > have the > problems either... now, i'm not sure, at all, if any of the (demo) > apps i'm > working with are using the libmysql.dll file that i placed in my > windows/system(32?) directory or not... i believe that the textmode > demo would > not run without that dll but that was several weeks ago when i was > playing with > it and it was also in the plain FPC 2.2.2 installation i have/had on > here before > i figured out that Laz came with FPC in its tree... > > for those who want/need a link to example code that exhibits this > problem, i'm > using the downloaded code "TryMySQL5 Modified by Arwen" but i can't > find the > link in the wiki now :( in any case, this is the TryMySQL5 demo app > with the > fields for the server, username, and password rather than them being > hardcoded... once you fill them in, then you click the [Connect] > button to > connect to the server and get a list of available databases... now > you choose a > database from the combo box and then click the [Select Database] > button... it is > at this point that the error is thrown when the connection is closed and > reopened so the new database can be used... > > > FWIW: > here's the memo field "log" with the error point marked with '>>' > and yes, i've > slightly modified the "logging" to try to figure out where the error > is taking > place and every time the last line logged before the popup box > appears is the > one right above the mysql50connection.close line... > > 14:26:18: Opening a connection to server: ender > 14:26:19: Connected to server: ender > 14:26:19: Retreiving list of available databases. > 14:26:19: Query ACTIVE and at the first record > 14:26:19: List of databases received! > >>14:26:26: Closing connection > 14:26:33: Closing connection > 14:26:33: Connection closed... > 14:26:33: DatabaseComboBox.ItemIndex: 2 > 14:26:33: DatabaseComboBox.Items[ItemIndex]: kims > 14:26:33: setting SQL statement... > 14:26:33: Retrieving list of tables > 14:26:33: opening sql query... > 14:26:34: List of tables received > > so, at 14:26:26, i clicked the [Select Database] button and then > clicked the > [OK] button in the error box and then i clicked on the [Select > Database] button > again (14:26:33)... > > so, there it is with all my wordiness and verbiage... oh, and the > hidden subtle > "am i linked?" test message ;) > > so, is it me or is it a bug in the library? if the library, which > library? Laz > stuff or FPC stuff? > > -- > NOTE: NEW EMAIL ADDRESS!! > > _\/ > (@@) Waldo Kitty, Waldo's Place USA > __ooO_( )_Ooo_____________________ telnet://bbs.wpusa.dynip.com > <http://bbs.wpusa.dynip.com> > _|_____|_____|_____|_____|_____|_____ http://www.wpusa.dynip.com > ____|_____|_____|_____|_____|_____|____ ftp://ftp.wpusa.dynip.com > _|_Eat_SPAM_to_email_me!_YUM!__|_____ wkitty42 -at- windstream.net > <http://windstream.net> > > > --- > avast! 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