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?
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