procedure MastertableBeforeDelete(DataSet: TDataSet);
begin
   with query do
    begin
    close;
    SQL.clear;
    SQL.Add('delete from table2 where table2."field" = :field);
     prepare;
       paramByName('field').asstring :=
mastertable.fieldbyname('field').asstring;
     open;
   end;
end;

There will not always be records in the detail table and if you have any
suggestions how to handle that I would appreciate it.

thanks a bunch

   Replace the "Open" statement with "ExecSql"

  Open, expects a cursor handle to come back from the BDE.  Here you are issuing
a command, and as such, opening not a thing.

   Alternatively,
   you can

   try
     Open
   except
   end;

   and ignore the error.

  Lotsa Luck.

 Joe.

I like routines like:

with masterQry do begin
  SQL.Clear;
{ I don't use parameters if I have to create the SQL statement anyway - just
make it part of the statement }
  SQL.Add( 'delete from mastertbl where MyID = ''5''');
  MyDbase.StartTransaction
  try
    execSQL;
    if RowsAffected = 1 then begin
      with detailQry do begin
        SQL.Clear;
        SQL.Add('delete from detailtbl where ParentID=''5''')
        execSQL;
    { no need to check for rowsaffected - if there were no details - who cares
if it failed }
      end;  {with detailQry}

     MyDBase.Commit;
    else
      raise exception.create('No master with ID=''5''');
  except
     on E: Exception do begin
       MyDBase.Rollback;
       MessageDlg( 'Could not delete' + #10 + E.Message, mtWarning, [mbOK], 0
);
    end;  {on Exception }
  end;  { except }