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We found an UNUSED COLUMN in a table, but we actually didn't mark any column as UNUSED on that table explicitly. We did drop a unique contraint and created a unique function based index on that table.
Does any body know that any side effect could result in a column getting UNUSED mark.
Thanks for any help.
A column marked as unused may still have data, but the column name will not be displayed in queries or data dictionary views. The name is removed from the data dictionary so that a new column can reuse that name. All constriants, indexes and statistics defined on the column are also removed.
Sounds strange ..
Unused columns as good as deleted columns
They cannot be accessed
Then cannot be exported
Yes if the UNUSED column hasn't affected any processes in your application and database, I'd say it'd be safe to drop. When DROP the unused column, just remember no DML can be performed on the table whilst this is occuring.. and if its a large table, that can take a while.
Cheers,