[Script] Check the existence of record before saving.

function CheckDublicate (Action, sTable, sField, sValue: string; id: integer;): boolean;
var
   s: string;
   sIdSQL: string;

   arrFields: array of string;
   arrValues: array of string;

   sWhere: string;
   i,c: integer;
begin
    result := False;
    arrFields := SplitString(sField, ';');
    arrValues := SplitString(sValue, ';');
    if Length(arrFields) <> Length(arrFields) then exit;

    sWhere := '';
    c := Length(arrFields)-1;
    for i := 0 to c do
    begin
        if arrValues[i] <> 'NULL' then
            sWhere := sWhere + arrFields[i]+' LIKE ' + arrValues[i] + ' AND '
        else sWhere := sWhere + arrFields[i]+' IS NULL AND '
    end;

    if sWhere<>'' then SetLength(sWhere, Length(sWhere)-4);

    if Action = 'NewRecord' then
    begin
          s := SQLExecute ('SELECT Count(*) FROM '+sTable+' WHERE '+sWhere);
          if StrToInt(s) > 0 then result := True;
    end;

    if Action = 'ShowRecord' then
    begin
          if id <> -1 then sIdSQL := ' AND (id <> '+ IntToStr(id) +')';
          s := SQLExecute ('SELECT Count(*) FROM '+sTable+' WHERE ('+ sWhere +') ' + sIdSQL);
          if StrToInt(s) > 0 then result := True;
    end;
end;



procedure frmEmployee_Button2_OnClick (Sender: string; var Cancel: boolean);
var
    sFields, sValues: string;
begin
    sFields := 'lastname;firstname';
    sValues := frmEmployee.edLastName.sqlValue+';'+frmEmployee.edFistName.sqlValue;

   if CheckDublicate(frmEmployee.dbAction, 'employees', sFields, sValues, frmEmployee.ButtonSave.dbGeneralTableId) then
   begin
        ShowMessage('Person already exists.');
        Cancel := True;
   end;
end;

begin
end.