The ##PD tag defines a parameter in the procedure call. The system will parse all the named parameters from the CREATE PROCEDURE definition for inclusion in the compiled help. Type information, input/output status, and default values are extracted. If no ##PD tag exists for a given parameter, there will be no description associated with it in the help, but the parameter will be named.
Since the ##PD is not legal SQL syntax, it must appear between comment tags. The tag may be between multiline comment tags (/* ... */), but only the first line will be read. If the ##PD line is intended to be a multiline comment, a ##PD must appear on the line immediately before the text to form part of the comment.
##PD Parameter Name ^^ Comment
Where Parameter Name is
the name of the parameter passed to the procedure,
and Comment is
the documentation text to use
-- ##PD Title ^^ The title of the book to be modified.
When SQLHelp parses the SQL forming the batch, it determines both the data type, and if the parameter is optional. If the parameter is required, this is indicated. If it is optional, the default value is supplied such that the user can know if the default is appropriate.