I have a stored procedure which takes a parameter, gets a value from
a table and inserts that value and the parameter into another table.
The SP executes correctly when run from a script editor, but I get an
error when I run it from Delphi (ver 4). I also get the error if I
try to open the TIB_StoredProc dataset.

Listed below is the error that is reported when I open the dataset.
As I noted, this SP runs perfectly in an editor.


ISC ERROR CODE:335544347

ISC ERROR MESSAGE:
validation error for column SHOWID, value "*** null ***"

STATEMENT:
TIB_Cursor: "frmWISQL.crEdit"

SQL ERROR CODE:-625

SQL ERROR MESSAGE:
The insert failed because a column definition includes validation
constraints.

I am sure there is a simple solution to this, but I am now learning
my way around Interbase / Delphi and any help would be appreciated.

Maxie