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 DOMAININDEX 

Version Count Increments

Some changes in the structure of a table increment the metadata change counter (“version count”) assigned to every table.The number of metadata changes is limited to 255 for each table, or 32,000 for each view.Once the counter reaches this limit, you will not be able to make any further changes to the structure of the table or view without resetting the counter.

To reset the metadata change counter
You need to back up and restore the database using the gbak utility.

The SET NOT NULL and DROP NOT NULL Clauses

The SET NOT NULL clause adds a NOT NULL constraint on an existing table column.Contrary to definition in CREATE TABLE, it is not possible to specify a constraint name.

Note

The successful addition of the NOT NULL constraint is subject to a full data validation on the table, so ensure that the column has no nulls before attempting the change.

An explicit NOT NULL constraint on domain-based column overrides domain settings.In this scenario, changing the domain to be nullable does not extend to a table column.

Dropping the NOT NULL constraint from the column if its type is a domain that also has a NOT NULL constraint, has no observable effect until the NOT NULL constraint is dropped from the domain as well.