Lazarus

Programming => Databases => Topic started by: Hansvb on June 20, 2022, 03:30:05 pm

Title: SqlQuery update status
Post by: Hansvb on June 20, 2022, 03:30:05 pm

Hi,

The user can make changes in a table via a DbGrid. Now I only want to save if there are actually mutations. How can you check for that?
I thought of doing this with SqlQuery.UpdateStataus. But this only seems to be activated if you first go to a following line in the DbGrid. I want to see the UpdateStatus change as soon as I exit the cell. Is that possible?

Code: Pascal  [Select][+][-]

1. procedure TFrm_Main.DBGridMain1ColExit(Sender: TObject);
2. begin
3.   case DataModuleMain.SQLQuery1.UpdateStatus of
4.    usUnmodified :  Button2.Caption:='usUnmodified';
5.    usModified :  Button2.Caption:='usModified';
6.    usInserted :  Button2.Caption:='usInserted';
7.    usDeleted :  Button2.Caption:='usDeleted';
8.   end;
9. end;  

Title: Re: het SqlQuery update status
Post by: Zvoni on June 20, 2022, 03:56:09 pm

Why not use OnSelection-Event?
You need variables for oldValue, oldRow and oldCol where you save Row and Col when selecting a cell
OnSelection ships Col and Row of the newly selected Cell
Compare newValue to oldValue of Cell at "old" Col/Row, if "dirty" then update. Set oldCol/oldRow to current Col/Row, oldValue to current value

Title: Re: SqlQuery update status
Post by: Hansvb on June 20, 2022, 07:47:47 pm

Found something which i can use: Datasource.state. if a cell in DbGrid is changed the datasource state changes.

To see what happens when a cell changes:

Code: Pascal  [Select][+][-]

1. procedure TDataModuleMain.DataSource1StateChange(Sender: TObject);
2. begin
3.   case DataSource1.State of
4.   dsInactive:
5.     begin
6.       ShowMessage('dsInactive');
7.     end;
8.   dsBrowse:
9.     begin
10.       ShowMessage('dsBrowse');
11.     end;
12.   dsEdit:
13.     begin
14.       ShowMessage('dsEdit');
15.     end;
16.   dsInsert:
17.     begin
18.       ShowMessage('dsInsert');
19.     end;
20.   dsCalcFields:
21.     begin
22.       ShowMessage('dsCalcFields');
23.     end;
24.   dsCurValue:
25.     begin
26.       ShowMessage('dsCurValue');
27.     end;
28.   dsNewValue:
29.     begin
30.       ShowMessage('dsNewValue');
31.     end;
32.   dsOldValue:
33.     begin
34.       ShowMessage('dsOldValue');
35.     end;
36.   dsFilter:
37.     begin
38.       ShowMessage('dsFilter');
39.     end;
40.   end;
41. end;