我可以使TADOStoredProc按名称将给定参数应用于目标过程吗？

Question

I am trying to call a stored procedure from delphi7. The procedure also contains parameters with default values. As far as I understand I can call this procedure without explicitly passing values for parameters, having defaults. That's what I did in my delpho code.

But..

The result of appeared to be confusing. The parameter I skipped did get some value. That was the value for the next parameter. And it appeared the last parameter that didn't get its value instead in the end.

I tried to search and found this article. So, it turns out to be, that delphi ignored the names I gave to the parameteres of the TADOStoredProc and just passed them in the order I added them to the parameters' collection, ie the last parameter (happily it was also optional and no exception was thrown) wasn't passed to the procedure.

I see the answer by @crefird, suggesting to use TADOQuery instead of TADOStoredProc. But I don't like the approach. I'd better give certain values to all the parameters and don't use the optional parameters feature at all.

So, is there a better solution to make delphi specify parameters to a stored procedure by their names, when using TADOStoredProc?

Answer 1

You could make a TADOStoredProc at design time and have it populate its parameters collection. If you don't have a form to put it on you could use a DataModule.

Years ago I learnt the same lesson as you - the parameter names are ignored. Maintaining and growing the codebase that uses Delphi & SQL Server over the past ten years has been made easier by putting any new SP parameters at the END of the parameter list and, if desired, making them optional.

I have seem people make the TADOStoredProc object and then call its refreshParams (or refreshParameters - not sure of the name) method. That would involve a whole extra trip to the database which is probably to be avoided.