Learn the essential features and functions of the popular JavaScript framework for building mobile, desktop and web applications.
Deleting & database triggers
I have a table, with a trigger on it wich prevents certain deletes.
A Delphi program tries to delete a record, but the trigger prevents it from being deleted. However, my delphi progam doesn't show the record anymore, unless i do a refresh. Is there an OTHER way (so without me doing a refresh) to keep on seeing that record ?
A Delphi program tries to delete a record, but the trigger prevents it from being deleted. However, my delphi progam doesn't show the record anymore, unless i do a refresh. Is there an OTHER way (so without me doing a refresh) to keep on seeing that record ?
Who is Participating?
Experts Exchange Solution brought to you by
Enjoy your complimentary solution view.
Get every solution instantly with Premium.
Start your 7-day free trial.
I wear a lot of hats...
"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.
Try adding some type of code into your trigger that forces a refresh when the trigger is triggered.... This way it will automatically refresh.
If this is the type of answer an expert gives, i'm also an expert. How can i get my SQL forcing a refresh of my Delphi Datasource ?
But i'd rather like my Delphi recognize the fact that the record still exists !
Hoping for a real answer !
But i'd rather like my Delphi recognize the fact that the record still exists !
Hoping for a real answer !
(Anyone who can point a browser to this site can probably
register as an expert too...)
Anyway for my real answer:
I do not know that database server you use but normally
your "Delete from ..." SQL will generate some sort of
error message when you execute it. (Although common sense suggests that you should receive an error message whenever the
delete fails...)
You should execute the SQL by hand and see what happens if
the trigger prevents the delete. If there is no error, you
have a problem at the server side (IMHO)
If there is an error, then you can catch that error in your code
and you bnever have to refresh in the first place.
Good Luck,
(And please, please please use the TSQL component,)
register as an expert too...)
Anyway for my real answer:
I do not know that database server you use but normally
your "Delete from ..." SQL will generate some sort of
error message when you execute it. (Although common sense suggests that you should receive an error message whenever the
delete fails...)
You should execute the SQL by hand and see what happens if
the trigger prevents the delete. If there is no error, you
have a problem at the server side (IMHO)
If there is an error, then you can catch that error in your code
and you bnever have to refresh in the first place.
Good Luck,
(And please, please please use the TSQL component,)
Isn't TSQL part of oracle ? I use M$ $QL$ERVER !
if a trigger does a rollback of the transaction, there is no real error occuring. It's just part of the business rules, that you can't delete a specific record. In MS SQLServer, Stored procedures can return a kind of status level, but triggers cannot. So i keep on looking for a solution ...
if a trigger does a rollback of the transaction, there is no real error occuring. It's just part of the business rules, that you can't delete a specific record. In MS SQLServer, Stored procedures can return a kind of status level, but triggers cannot. So i keep on looking for a solution ...
Jeez... almost to simple to warrant an answer, but here goes anyway...
If the trigger causes a rollback (failed delete) then INSIDE the trigger issue a RAISERROR statement that you can capture with Delphi to indicate that yes, the delete was *attempted* but it failed due to a business rule conflict. When you issue the RAISEERROR statement try and use an error code that is not normally in use by MS SQL Server but is meaningful in the context of your application/business rules.
When Delphi recieves anything other than a successful completion code (0) back from the server it assumes there was a failure of that operation (be it Update, Delete or Insert) and WILL NOT remove that record from the result set on the client side.
The apps I'm working with do this on a regular basis, it's part of standard SQL knowledge in regard to client/server architecture :P
Good luck with your project
Pegasus
If the trigger causes a rollback (failed delete) then INSIDE the trigger issue a RAISERROR statement that you can capture with Delphi to indicate that yes, the delete was *attempted* but it failed due to a business rule conflict. When you issue the RAISEERROR statement try and use an error code that is not normally in use by MS SQL Server but is meaningful in the context of your application/business rules.
When Delphi recieves anything other than a successful completion code (0) back from the server it assumes there was a failure of that operation (be it Update, Delete or Insert) and WILL NOT remove that record from the result set on the client side.
The apps I'm working with do this on a regular basis, it's part of standard SQL knowledge in regard to client/server architecture :P
Good luck with your project
Pegasus
Experts Exchange Solution brought to you by
Your issues matter to us.
Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.
Start your 7-day free trial
Jvh,
It was not a "stupid" question at all, just one that I assumed everyone was familiar with how to handle. Bad assumption on my part. Anyways, glad to see everything is working ok.
On to the next bug! :)
Pegasus
It was not a "stupid" question at all, just one that I assumed everyone was familiar with how to handle. Bad assumption on my part. Anyways, glad to see everything is working ok.
On to the next bug! :)
Pegasus
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Delphi
From novice to tech pro — start learning today.
-
Microsoft ApplicationsCertification: MOS Microsoft Office Specialist - Word 2013 Part … 120 lessons
-
Microsoft ApplicationsCertification: MOS Microsoft Office Specialist - PowerPoint 2007… 229 lessons
-
Business CommunicationCertification: PMI RMP Project Management Institute Risk Management… 113 lessons
Experts Exchange Solution brought to you by
Enjoy your complimentary solution view.
Get every solution instantly with Premium.
Start your 7-day free trial.