The NOT NULL constraint in DB2 ensures that a column ________.

The NOT NULL constraint in DB2 ensures that a column must contain non-NULL values, meaning every row in the column must have a value assigned to it and cannot be left empty. This constraint guarantees the presence of data in the specified column, thereby preventing the insertion of NULL values, which can lead to data inconsistency or errors in queries and calculations. It ensures data integrity and helps enforce business rules regarding mandatory data entry.