obtain customer_id automatically on new record - delphi

Question

I am pulling down records with a stored procedure of customers that have a customer_id=5.
Now the procedure gets the data and shows it in the grid and I want to add a new record .
How can I make sure that when I add new record in the grid it has automatically the same customer_id ( 5 ) ?
I dont want to write it down all the time.I used to know this but I forgot.The DB is sql server.

Answer 1

You can set the DefaultExpression to the used ID for the field you want. For example for a UniDAC stored procedure object you can do (ParamCustID is the procedure input parameter, FieldCustID is the returned dataset field name):
var
CustID: Integer;
begin
CustID := 123;
UniStoredProc1.StoredProcName := 'MyProcedure';
UniStoredProc1.PrepareSQL;
UniStoredProc1.ParamByName('ParamCustID').AsInteger := CustID;
UniStoredProc1.Execute;
UniStoredProc1.FieldByName('FieldCustID').ReadOnly := True;
UniStoredProc1.FieldByName('FieldCustID').DefaultExpression := IntToStr(CustID);
end;
The above code will setup the field for assigning same value for every appended tuple, and makes it read only. Out of curiosity, the same task for FireDAC would go like this (for applying changes, there must be an explicit method call for updating field attributes):
var
CustID: Integer;
begin
CustID := 123;
FDStoredProc1.StoredProcName := 'MyProcedure';
FDStoredProc1.Prepare;
FDStoredProc1.ParamByName('#ParamCustID').AsInteger := CustID;
FDStoredProc1.Open;
FDStoredProc1.FieldByName('FieldCustID').ReadOnly := True;
FDStoredProc1.FieldByName('FieldCustID').DefaultExpression := IntToStr(CustID);
FDStoredProc1.UpdateAttributes;
end;