TSQLQuery : How to lock the recording before UpdateSQL ?
lazarus / 16-Databases

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Pabdym · 2012-09-30 16:39

Hi,
QuotepgConn : TPQConnection
Transaction ->pgTransHostName, ... ->[...]
pgTrans : TSQLTransaction
Action -> caCommitDatabase -> pgConn
pgQuery : TSQLQuery
Database -> pgConnTransaction -> pgTransSQL -> 'SELECT * FROM
dev2012hg;'
InsertSQL->'INSERT INTO dev2012hg (hgid, hglogiciel, hgversion,
hgprogrammeur, hgtext) VALUES (:hgid, :hglogiciel, :hgversion,
:hgprogrammeur, :hgtext);'UpdateSQL-> 'UPDATE dev2012hg set hglogiciel
= :hglogiciel, hgversion = :hgversion, hgprogrammeur = :hgprogrammeur
WHERE hgid = :old_hgid;'pgDataSource : TDataSource
DataSet -> pgQuerypgDBNavigator : TDBNavigator;
DataSource -> pgDataSourceOther parameters of the 4 components : by
default.

My codes :
Code: [Select]procedure TForm1.Button1Click(Sender: TObject);
begin
  pgConn.Connected:= True;
  pgQuery.Open;
end;

procedure TForm1.pgQueryAfterPost(DataSet: TDataSet);
 var
  pgBooKMark: TBookMark;
begin
  try
    TSQLQuery(DataSet).ApplyUpdates;
    TSQLTransaction(TSQLQuery(DataSet).Transaction).Commit;
  except
    on E: Exception do begin
      Showmessage('Problem with updating: ' + E.Message);
      TSQLTransaction(TSQLQuery(DataSet).Transaction).Rollback;
    end;
  end;
  TSQLQuery(DataSet).Close;
  TSQLQuery(DataSet).Open;
end;

It works fine, but I need to lock my recording before update or
delete.  With 2 TSQLQueries (that of Datasource and the other reserved
to lock), it seems to be OK. But, is it the good method ?With a single
TSQLQuery (that of Datasource), is it possible to lock the recording
before update (or delete) ?
Thanks.