long raw null values

How do you tell whether a LONG RAW column contains data or is null?. I have a table with a number of different types of information, some of which use the long raw column contained in the table and some which do not.

When I do a count of the rows that should not have valid long raw data in them using the query:

select count(*) from 'table name' where 'long raw column' is not null;

I get back a non zero count. (I also get a count back when using a query with the where clause 'is null', as expected).

No data is explicitly being put into the long raw column for these rows. Why do I get a count when there should be no rows matching the criteria. I vaguely remember reading an article some time ago talking about the use of nulls and getting incorrect sql returns if nulls are used wrongly in the query. If I have not explicitly set the long raw column to null when creating the row in the first place will it contain 'vague' data that gets picked up in the query.

Any information on this area would be greatly appreciated, I`m new to the oracle game and especially to the use of long raw datatypes. Received on Mon Mar 22 1999 - 07:30:16 CST