Access violation error at address in TOraQuery Component ...

sshamiluulu · Post by **sshamiluulu** » Wed 01 Dec 2010 14:02

Hello everyone,
Let me first explain what I am trying to do and the problem I am facing.
1. We have a project written on Delphi 5 that has to be converted to Delphi 2010 due to character set problems and usage of Unicode. Our underlying database is oracle 10g.
First I tested all needed components including ODAC as a trial version. Later on we bought all needed components including ODAC.
[b]Problem:[/b] After I bought ODAC components removed trial version and installed them to Delphi 2010 RAD without any problem. Today I wrote very simple program on Delphi 2010 so I placed all the needed ODAC components like OraSession, OraQuery etc., so when I click on OraQuery enter an SQL statement inside and press the buttons Execute or Data Editor it gives me an error NET: Access violation at address ... or NULL pointer etc. The same program works perfect on Delphi 5

What is the problem ?

AlexP · Post by **AlexP** » Thu 02 Dec 2010 08:55

Hello,

I could not reproduce the problem.
Please try to reinstall ODAC, create a new project, add only the TOraSession and TOraQuery components, configure the connection properties, press the Connect button, and set the SELECT * FROM DUAL SQL statement. If the problem arises again, please contact me.
Also this problem may be connected with some other third-party components, you can try to install ODAC to a "clear" Deplhi 2010 and run your test project.

sshamiluulu · Post by **sshamiluulu** » Thu 02 Dec 2010 13:58

[quote="AlexP"]Hello,
I could not reproduce the problem.
Please try to reinstall ODAC, create a new project, add only the TOraSession and TOraQuery components, configure the connection properties, press the Connect button, and set the SELECT * FROM DUAL SQL statement. If the problem arises again, please contact me.
Also this problem may be connected with some other third-party components, you can try to install ODAC to a "clear" Deplhi 2010 and run your test project.[/quote]

Hello AlexP
First of all thank you for your reply.
I reinstalled the ODAC component but the error did not change.
After that I by chance saw something very interesting and at the same time strange.
1. I have to databases one is local one that is Oracle 11g on Win 7 machine and second is remote on the network(i.e., Oracle 10g). ODAC components(TOraSession) can without any difficulties connect to local machines database and retrieve data(TOraQuery) without any difficulty, it it is able to connect to remote database BUT cannot retrieve that from remote database host.
Why it cannot retrieve ?
I am attaching an image for more clarity
I deliberately over painted server in torasession

thank you

AlexP · Post by **AlexP** » Fri 03 Dec 2010 11:55

Hello,

Please try to connect to the remote database from any other applications like OraDeveloper Studio, SQL Navigator, etc., and execute any query.
Also please specify if you were able to connect to the remote host using the trial version of ODAC.

sshamiluulu · Post by **sshamiluulu** » Tue 07 Dec 2010 10:08

The problem has been solved with odac 7.00.0.2 update
In odac 7.00.0.1 there was an error.