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Report From: Delphi-BCB/Midas/TDataSetProvider [ Add a report in this area ]

Report #: 4006

Status: Closed

DB 'current' values after an update conflict (Record not found or changed by another user) is against the wrong fields

Project: Delphi

Build #: 6.240

Version: 7.0

Submitted By: Dave Rowntree

Report Type: Basic functionality failure

Date Reported: 4/4/2003 9:02:00 AM

Severity: Commonly encountered problem

Last Updated: 10/6/2006 6:50:56 AM

Platform: 95, 98, 2000, NT, XP

Internal Tracking #: 159437

Resolution: Fixed (Resolution Comments)

Resolved in Build: : 7.0.8.1

Duplicate of: None

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Total Votes: None

Description

When the DSP obtains the DB 'current' values after an update conflict (Record not found or changed by another user), it does so against the wrong fields. The fields it requests current values for should be the same as the fields in the update where clause, but they are not.

DSP.GenSelectSQL generates the select statement (for TSQLResolver.InitializeConflictBuffer) and it's field selection criteria is incorrect.

DSP.GenSelectSQL is also called by TDataSetProvider.GetDataSetFromDelta, which is used by CDS.RefreshRecord. The field selection criteria is incorrect for that requirement as well (see QC????). Since the field selection criteria is different for these two requirements, two seperate functions would seem to be the way to go.

Steps to Reproduce:

1. download the test case app from Attachments.
2. Open the test case app in Delphi.
3. Follow the on screen steps.

Workarounds

PROVIDER.PAS
(**) (* Delphi 6.0 - 7.01 *)
(* Fix to correct the obtaining of current db values after an update
   conflict. This fix returns current values for fields that would
   have been in the update 'where' clause. Without this fix, just
   fields containing a pfInWhere flag have current values returned *)
(* Dave Rowntree 04/01/03 *)
procedure TSQLResolver.InitializeConflictBuffer(Tree: TUpdateTree);
var
  Alias: string;

(**) (* add this function *)
  function GenConflictSelectSQL(Tree: TUpdateTree; SQL: TStrings):Boolean;
  var
    i: Integer;
    Temp: string;
  begin
    Result := False;
    with PSQLInfo(Tree.Data)^ do
    begin
      SQL.Add('select');
      for i := 0 to Tree.Delta.FieldCount - 1 do
        if UseFieldInWhere(Tree.Delta.Fields[i], Provider.UpdateMode) then
        begin
          SQL.Add(Format(' %s%s%s%1:s,',
            [QuotedTableDot, QuoteChar, Tree.Delta.Fields[i].Origin]));
          Result := True;
        end;
      if Result then
      begin
        { Remove last ',' }
        Temp := SQL[SQL.Count-1];
        SQL[SQL.Count-1] := Copy(Temp, 1, Length(Temp) - 1);
        SQL.Add(Format(' from %s %s',[QuotedTable, Alias]));     { Do not localize }
      end;
    end;
  end;

begin
  if PSQLInfo(Tree.Data)^.HasObjects then Alias := DefAlias else Alias := '';
  FSQL.Clear;
  FParams.Clear;
  //GenSelectSQL(Tree, FSQL, FParams, Alias);               (**) (* rem out this line *)
  if GenConflictSelectSQL(Tree, FSQL) then                  (**) (* add this line *)
  begin                                                     (**) (* add this line *)
    GenWhereSQL(Tree, FSQL, FParams, upWhereKeyOnly, Alias);(**) (* add this line *)
    DoGetValues(FSQL, FParams, Tree.Delta);                 (**) (* add this line *)
  end;                                                      (**) (* add this line *)
end;

---------

PROVIDER.PAS
(**) (* Delphi 6.0 - 7.01 *)
(* Fix to correct the obtaining of current db values after an update
   conflict. This fix returns current values for fields that would
   have been in the update 'where' clause. Without this fix, just
   fields containing a pfInWhere flag have current values returned *)
(* Dave Rowntree 04/01/03 *)
procedure TSQLResolver.InitializeConflictBuffer(Tree: TUpdateTree);
var
  Alias: string;

(**) (* add this function *)
  function GenConflictSelectSQL(Tree: TUpdateTree; SQL: TStrings):Boolean;
  var
    i: Integer;
    Temp: string;
  begin
    Result := False;
    with PSQLInfo(Tree.Data)^ do
    begin
      SQL.Add('select');
      for i := 0 to Tree.Delta.FieldCount - 1 do
        if UseFieldInWhere(Tree.Delta.Fields[i], Provider.UpdateMode) then
        begin
          SQL.Add(Format(' %s%s%s%1:s,',
            [QuotedTableDot, QuoteChar, Tree.Delta.Fields[i].Origin]));
          Result := True;
        end;
      if Result then
      begin
        { Remove last ',' }
        Temp := SQL[SQL.Count-1];
        SQL[SQL.Count-1] := Copy(Temp, 1, Length(Temp) - 1);
        SQL.Add(Format(' from %s %s',[QuotedTable, Alias]));     { Do not localize }
      end;
    end;
  end;

begin
  if PSQLInfo(Tree.Data)^.HasObjects then Alias := DefAlias else Alias := '';
  FSQL.Clear;
  FParams.Clear;
  //GenSelectSQL(Tree, FSQL, FParams, Alias);               (**) (* rem out this line *)
  if GenConflictSelectSQL(Tree, FSQL) then                  (**) (* add this line *)
  begin                                                     (**) (* add this line *)
    GenWhereSQL(Tree, FSQL, FParams, upWhereKeyOnly, Alias);(**) (* add this line *)
    DoGetValues(FSQL, FParams, Tree.Delta);                 (**) (* add this line *)
  end;                                                      (**) (* add this line *)
end;

Attachment

4006.zip

Comments

Daniel Serrano at 1/26/2007 8:00:07 PM -

HI:

I have the same error, please send me the fix. is very important.

Greetings from Per

Daniel Serrano

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