Exam C2090-600 topic 1 question 46 discussion

The correct answer is well "D- 4" because the keyword "NOT ENFORCED" is used with the primary key. See reference : https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.1.0/com.ibm.db2.luw.admin.dbobj.doc/doc/c0023324.html You can create a not-enforced primary key or unique constraint for either a column-organized or row-organized table. Unlike an enforced primary key or unique constraint, a not-enforced primary key or unique constraint does not create an index on the data. Specify an informational constraint only if the table data is independently known to conform to the constraint. Because the Db2® database manager does not enforce uniqueness for these constraints, if the table data violates the not-enforced constraint, incorrect results can occur. You cannot reference not-enforced primary key constraints in any enforced referential integrity definitions.