Delphi & Absolute database : Delete Query

Question

Why is it that my query does not work ?

Form1.ABSQuery1.Close;
Form1.ABSQuery1.SQL.Clear;
Form1.ABSQuery1.SQL.Text:='DELETE FROM LOG WHERE status = ''YES'' and DATE BETWEEN :d1 and :d2';
Form1.ABSQuery1.Params.ParamByName('d1').Value :=cxDateEdit1.Date;
Form1.ABSQuery1.Params.ParamByName('d2').Value :=cxDateEdit2.Date;
Form1.ABSQuery1.ExecSQL;
Form1.ABSTable1.Refresh;

I get this error :

Answer 1

You should be using AsDateTime in your Params setting code.

Form1.ABSQuery1.SQL.Text:='DELETE FROM LOG WHERE status = ''YES'' and DATE BETWEEN :d1 and :d2';
Form1.ABSQuery1.Params.ParamByName('d1').AsDateTime :=cxDateEdit1.Date;
Form1.ABSQuery1.Params.ParamByName('d2').AsDateTime :=cxDateEdit2.Date;
Form1.ABSQuery1.ExecSQL;

Using Value converts the cxDateEdit1.Date to a generic string format for assignment, and that doesn't properly convert it to the YYYY-MM-DD format that most databases (including ABS) expect. Properly using AsDateTime allows the database driver/component to convert to the specific date format the DBMS uses.

Also, is your database field really named DATE? Date is usually a reserved word or function name in most DBMS, and if it is it usually needs to be quoted.

Answer 2

Form1.ABSQuery1.Params.ParamByName('d1').DataType := ftDateTime;
Form1.ABSQuery1.Params.ParamByName('d1').Value :=cxDateEdit1.Date;

You must explicitly specify the data type of the parameter to it had no such problem, and then convert to a string does not need to