我在Tfrmupload.FormCreate中使用以下代码连接数据库,但提示红钯部分未定义。如果定义需要怎么赋值? 
Connection:=CreateOleObject('ADODB.Recordset');
Connection.Open('Drive=(Driver={sql server};server=192.168.200.200;database=herbalist;uid=herbalist;pwd=herbalist'); 
Recordset:=CreateOleObject('ADODB.Recordset');   
Recordset.Open('select kt_id,kt_name from tblSubject',Connection,adOpenStatic,adLockOptimistic,adCmdTable);   
Recordset.First;   
combobox1.Items.Clear;   
while not Recordset.Eof do   
begin      
combobox1.Items.Add(Recordset.fields('kt_name').Value);       
Recordset.Next;   
end;