Вычисляемое поле SQLQuery1
lazarus / 16-Databases

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maxika · 2018-09-08 16:35

Hello, tell me please how to make an automatic calculation of the
calculated field SQLQuery1, when changing another numeric field.
When I do this:

procedure TForm1.SQLQuery1Поле1Change(Sender: TField);
begin
SQLQuery1.FieldByName('ВычислПоле')
.AsInteger:=SQLQuery1.FieldByName(' Поле1').AsInteger * 2;
end;

The auto save function stops working:

procedure TForm1.SQLQuery1AfterPost(DataSet: TDataSet);
begin
SQLQuery1.ApplyUpdates;
end;

Please tell me how to do it correctly.

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lucamar · 2018-09-08 18:18

Shouldn't ApplyUpdates be called much earlier? IIRC, in AfterPost the
dataset is already updated. Maybe you should try to set the calculated
field(s) and call ApplyUpdates in an OnBeforePost handler?

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maxika · 2018-09-09 14:24

thank you very much for the help
the following methods create an auto-calculation field and autosave
data

procedure TForm1.SQLQuery1BeforeScroll(DataSet: TDataSet);
begin
  SQLQuery1.Edit;
  SQLQuery1.FieldByName('AAA').AsInteger:=SQLQuery1.FieldByName('BBB')
.AsInteger*2;
  SQLQuery1.Post;
end; 

procedure TForm1.DBNavigator1Click(Sender: TObject; Button:
TDBNavButtonType);
begin
  if Button = nbPost then
   begin
     SQLQuery1.Edit;
     SQLQuery1.FieldByName('AAA').AsInteger:=SQLQuery1.FieldByName('BB
B').AsInteger*2;
     SQLQuery1.Post;
   end;
end;   

procedure TForm1.SQLQuery1AfterPost(DataSet: TDataSet);
begin
  SQLQuery1.ApplyUpdates;
end;

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sash · 2018-09-09 22:08

Usually for calculated fields (TFieldKind = fkCalculated) they use
OnCalcFields.

But seems like you're using regular fields, so:

don't (ever) use for such purpose

BeforeScroll
DBNavigatorClick

use

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.SQLQuery1BeforePost(DataSet: TDataSet);begin 
SQLQuery1.FieldByName('AAA').AsInteger :=
SQLQuery1.FieldByName('BBB').AsInteger*2;end;    procedure
TForm1.SQLQuery1AfterPost(DataSet: TDataSet);begin 
SQLQuery1.ApplyUpdates;end;   

p.s. Заголовки лучше писать по Английски.