i'm using D7 and connecting to an oracle database via an ADO connection component. using TClientDataSet and TDataSetProvider components. i first qry for data using an ADO query component that i create on the fly (in code). once the query finishes i use the following lines of code to populate / prepare the TClientDataSet and TDataSetProvider components to open:
OnTheFlyQuery.Open;
ClientDataSet1.FieldDefs.C
DataSetProvider1.DataSet := OnTheFlyQuery;
ClientDataSet1.ProviderNam
DataSetProvider1.GetRecord
ClientDataSet1.Open;
I use the TClientDataSet and TDataSetProvider components because the results returned from the OnTheFlyQuery will more than likely be more than one record and I may need to loop throught these records later on whill other queries are running so i wanted to keep the records local.
My problem is that the OnTheFlyQuery can sometimes take 10 - 15 mins and right now fixing that problem is out of my hands. When it does take that long I get an Access violation on the ClientDataSet1.Open line, if it does finish in a reasonable time then i'm still getting a: "EDatabaseError with message "Invalid filter expression character: ¬" error message. If I change the CommandTimeout of the OnTheFlyQuery or the TADOConnection components to be 6300 secs (15 min) then I still get the EDatabasError but no access violation error. Any ideas / suggestions?
This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.
Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.
If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.
Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.
Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.
Access the answers to your technology questions today.
30-day free trial. Register in 60 seconds.
Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.
Try it out and discover for yourself.
30-day free trial. Register in 60 seconds.
Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.
>The OnTheFlyQuery is a simple select:
>SELECT field1 FROM TableA WHERE field2 = X
15 minutes for this? Yiikes! How big is this table?
> OnTheFlyQuery.Open;
> ClientDataSet1.FieldDefs.C
> DataSetProvider1.DataSet := OnTheFlyQuery;
> ClientDataSet1.ProviderNam
> DataSetProvider1.GetRecord
> ClientDataSet1.Open;
AFAIK, you don't need the DataSetProvider1.GetRecord
automatically by the Clientdataset1.Open and is just a waste of time as
you're doubling the fetching. If you want to use this, do this way:
Delphian
I have also noticed that i get a "Invalid Pointer" error when attempting to close the ClientDataSet component. I'm sure there are many possiblities for this but are there any immediate checks that come to mind, that I should perform on the ClientDataSet component (in the debugger or in code) before i close it?
This kind of weird problems often arise from design-time events. So, look for events related
to the clientdataset, datasetprovider or even a TDataSource associated with the clientdataset.
Anything that use a reference to a run-time field, or even a invalid bookmark is suspect.
P.S: Hmmm... Have you heard about MadExcept? It's invaluable to me when needed to track
those type of exceptions. (http://www.madshi.net). Just a suggestion.
Business Accounts
Answer for Membership
by: mikesExpertExchangePosted on 2008-07-15 at 14:01:13ID: 22011104
sorry the line of code above that reads:
ClientDataSet1.ProviderNam
should read:
ClientDataSet1.ProviderNam