What am I doing wrong?

DaveRowland · Post by **DaveRowland** » Mon 19 Feb 2007 23:25

I have a window using a TMyQuery object to point to a table on the database and have set up the insert, delete and update SQL commands.

I have set cachedupdates ON.

I retrieve the information fine and it displays fine.

If I edit a column and call the ApplyUpdates method, the database gets updated.

My problem is, if I do change columns in edit fields on the window, the UpdatesPending always returns FALSE and the UpdateStatus always returns usUnmodified.

According to the online help, these should return possitive when the data has been altered for a cachedupdate.

How am I suppose to tell when changes have been made to the dataset prior to doing an update?

I need to know as I do not want to always tell the user to save their changes if there is nothing to save.

Antaeus · Post by **Antaeus** » Tue 20 Feb 2007 08:06

What MyDAC version are you using? Are you able to reproduce this problem in the CachedUpdates demo of MyDAC?
You can find this demo in %MyDAC%\Demos\ directory. %MyDAC% is the MyDAC installation path on your computer.

DaveRowland · Post by **DaveRowland** » Tue 20 Feb 2007 22:44

Antaeus wrote:What MyDAC version are you using?

I am using the latest objects. They have just been downloaded.
4.40.0.22

Antaeus wrote:Are you able to reproduce this problem in the CachedUpdates demo of MyDAC?

No, this seams to work.

The difference is that the demo uses a grid control where as I use dbedit controls on my form.

The window I am displaying the information on only contains one row as it is for opening and editing one client.

I would asume that, as I can change the columns on the client table by changing the data in the dbedit columns and performing an applyupdates, if I was to change the data for a column I can check for this change using either the UpdatesPending or UpdateStatus methods.

However, it does not matter how many items I change on the window, UpdatesPending always returns false and UpdateStatus always returns usUnmodified.

It seams that maybe these two methods are looking at a differnent row on the dataset then the current row being edited.

Am I using these methods correctly? The online help for these methods seams very vague.

Is there suppose to be a property or method I can poll to tell me if there are any inserts, deletes or updates pending against the entire dataset?

Antaeus · Post by **Antaeus** » Wed 21 Feb 2007 12:40

I modified the CachedUpdates demo so that data is displayed in the DBEdit controls instead of DBGrid. While testing this project I did not notice any problems. The UpdatesPending and UpdateStatus properties were working correctly.
Please modify the CachedUpdates demo so that the problem is reproduced and send me this demo at evgeniyd*crlab*com.

DaveRowland · Post by **DaveRowland** » Wed 28 Feb 2007 02:06

I have emailed you a modified version of the demo app which also shows the problem I am experiencing.

It seams that the UpdatesPending flag is not being set unless I change current rows, however the window I am working on only has one row therefore I do not need to change it.

Antaeus · Post by **Antaeus** » Thu 01 Mar 2007 08:42

Thank you for your sample. If you edited a record but did not post it, the record status is not changed (UpdatesPending state is not changed too). It will change after you apply changes to dataset. So, try to check the dataset state before checking the UpdatesPending property. This may look like the following:

Code: Select all

  if MyQuery.State = dsEdit then
    MyQuery.Post;

  if MyQuery.UpdatesPending then
    Label10.Caption:= 'True'
  else
    Label10.Caption:='False';

DaveRowland · Post by **DaveRowland** » Thu 01 Mar 2007 22:52

Thanks for your reply.

There is no mention of this in the online help which is where we tend to get stuck.

I just wish Borland will make their help system a lot more intutative then what it currently is.

I have got it working now. Thanks and hopefully this will also help other newbies who have the same problem in their code.