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rain

Member

Registered: 2014-07-12

Posts: 8

strange behaviour of TSynDBDataSet with Firebird using Firedac

Hi,

I have derived a simple component from TSynDBDataSet to override InternalInitFieldDefs procedure.

The component seem work fine except when I edit a record with 2 VarChar(2) field one with '13' and the next empty if the field are on a form with 2 Dbedit and I use Tab to cycle from Dbedit to another the value of the first field is copied to the next field.

procedure TMyMemDataSet.InternalInitFieldDefs;
var
  lFields: TSQLDBColumnDefineDynArray;
  DBType: TFieldType;
  F: integer;
begin

  if FieldDefs.Count > 0 then
    exit;

  if Connection = nil then
    exit;
  Connection.GetFields(PSGetTableName, lFields);
  for F := Low(lFields) to High(lFields) do
  begin
    with lFields[F] do
    begin
      case ColumnType of
        SynCommons.ftInt64:
          begin
            DBType := db.ftLargeint;
          end;
        SynCommons.ftDate:
          begin
            DBType := db.ftDateTime;
          end;
        SynCommons.ftUTF8:
          if (ColumnLength = 0)  then
          begin
            DBType := db.ftWideMemo;
          end
          else
          begin
            DBType := db.ftWideString;
          end;
        SynCommons.ftBlob:
          begin
            DBType := db.ftBlob;
          end;
        SynCommons.ftDouble, SynCommons.ftCurrency:
          begin
            DBType := db.ftFloat;
          end
      else
        raise EDatabaseError.CreateFmt('GetFieldData ColumnType=%d', [ord(ColumnType)]);
      end;
      FieldDefs.Add(UTF8ToString(ColumnName), DBType, ColumnLength);
    end;
  end;
  setLength(lFields, 0);

end;

p.s. I'm using Delphi XE 10.1

TIA

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The mind is like a parachute, it only works if you open it.
Albert Einstein

rain

Member

Registered: 2014-07-12

Posts: 8

Re: strange behaviour of TSynDBDataSet with Firebird using Firedac

Hi,
I have found a possible cause in SynDBMidasVCL the TSynDBDataSet use a Dataset TSynDBSQLDataSet associated with the TDataSetProvider. If I override the InternalInitFieldDefs procedure of TSynDBSQLDataSet seem to work correctly

procedure TSynDBSQLDataSet.InternalInitFieldDefs;
var F: integer;
  DBType: TFieldType;
  lFields: TSQLDBColumnDefineDynArray;
begin

  FieldDefs.Clear;
  if fconnection = nil then
    exit;

  fconnection.GetFields(PSGetTableName, lFields);
  for F := Low(lFields) to High(lFields) do
  begin
    with lFields[F] do
    begin
      case ColumnType of
        SynCommons.ftInt64:
          begin
            DBType := db.ftLargeint;
          end;
        SynCommons.ftDate:
          begin
            DBType := db.ftDateTime;
          end;
        SynCommons.ftUTF8:
          begin
            if ColumnLength = 0 then
            begin
              DBType := db.ftWideMemo;
            end
            else
            begin
              DBType := db.ftWideString;
            end;

          end;
        SynCommons.ftBlob:
          begin
            DBType := db.ftBlob;
          end;
        SynCommons.ftDouble, SynCommons.ftCurrency:
          begin
            DBType := db.ftFloat;
          end
      else
        raise EDatabaseError.CreateFmt('GetFieldData ColumnType=%d', [ord(ColumnType)]);
      end;
      FieldDefs.Add(UTF8ToString(ColumnName), DBType, ColumnLength);
    end;
  end;
  setLength(lFields, 0);
end;

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The mind is like a parachute, it only works if you open it.
Albert Einstein