On Wed, Nov 22, 2006 at 09:48:40AM -0200, Marco T?lio Gontijo e Silva wrote: > Package: libghc6-hdbc-dev > Version: 1.0.1.1 > Severity: important > Tags: patch > > It's not possible to compare SqlNull to any other constructor of SqlType. > > Prelude Database.HDBC> SqlString "Marco" == SqlNull > *** Exception: fromSql: cannot convert SqlNull to String > > This is specially bad when I want to filter all the SqlNull from a list of > SqlTypes.
Hello Marco, Thank you for reporting the bug. However, I believe that it is not a bug, and that your suggested fix could be harmful. The problem with converting a SQL NULL into a string is that you could have that string stored in SQL. You should really be comparing to a (Just String) or Nothing, as in: Prelude Database.HDBC> fromSql (SqlString "Marco") == "Marco" True Prelude Database.HDBC> fromSql (SqlString "Marco") == Nothing False Prelude Database.HDBC> fromSql SqlNull == Nothing True Prelude Database.HDBC> fromSql (SqlString "Marco") == Just "Marco" True My current plan is to close this bug without making a change, but I'd like to hear your response first. -- John -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
