DescribeParams = true raises Data type not supported error

[upscene]

Hi,

I have Options.DescribeParams set to True on a TIBCQuery. When I prepare a query like this:

Code: Select all

select *
from rdb$database
where :p is null

I get "Data type is not supported". I fully understand that this works fine if I set DescribeParams to False, but in my application, I try to display the data type for parameters before users enter values.

Now, wouldn't it be better if the data type for this parameter simply stayed "ftUnknown" instead of raising the error? The user then could select a data type or keep the item Null.

With regards,

Martijn Tonies
Upscene Productions

[ViktorV]

If you want IBDAC not to generate the "Data type is not supported" error when DescribeParams is enabled, please post this suggestion at our user voice forum: https://devart.uservoice.com/forums/104 ... e-firebird If the suggestion gets a lot of votes, we will consider the possibility to implement it.

[upscene]

Would it be hard to implement?

[ViktorV]

The "Data type is not supported" error generated when DescribeParams is enabled - is the standard behavior of our components, which is used by many our users. If your suggestion at https://devart.uservoice.com gets enough votes, we will consider the possibility to implement it.

[upscene]

I doubt it would be very high on the list.

This could be made backwards compatible easily with either an additional option or .Prepare parameter.

Currently, the exception message ignores the ability for users/developers to fetch parameter types where possible and set those themselves when needed.

Is the exception raised when the DBMS returns "unknown"?

[ViktorV]

Please clarify, what do you mean by "the DBMS returns "unknown"?

[upscene]

"unknown" for the parameter data type when trying to figure it out?

[ViktorV]

We will investigate the possibility to implement this functionality in one of the next versions of IBDAC.

[upscene]

Thank you, for interactive applications, detecting parameter data types where possible and let the user decide what data type the "unknown"s are, is very helpful.

[ViktorV]

If you have any questions during using our products, please don't hesitate to contact us - and we will try to help you solve them.