IBM Certification SQL Database 4

Question 1

Which SQL statement is used to change the structure of an existing table by adding a column?

Accepted Answer

ALTER TABLE

Answer

ALTER TABLE ... ADD COLUMN modifies an existing table's schema without dropping and recreating it.

Question 2

In IBM Db2, what is a tablespace?

Accepted Answer

A storage structure that maps database objects to physical storage

Answer

A tablespace is a logical storage container that maps database tables and indexes to specific physical storage locations or storage groups.

Question 3

What is the purpose of the SQL EXCEPT operator?

Accepted Answer

Returns rows from the first result set not present in the second

Answer

EXCEPT returns distinct rows from the first SELECT that do not appear in the second SELECT's result set (called MINUS in some databases).

Question 4

Which normal form eliminates transitive dependencies among non-key attributes?

Accepted Answer

Third Normal Form (3NF)

Answer

Third Normal Form (3NF) requires that no non-key attribute is transitively dependent on the primary key through another non-key attribute.

Question 5

In SQL, what does a FULL OUTER JOIN return?

Accepted Answer

All rows from both tables with NULLs where there is no match

Answer

A FULL OUTER JOIN returns all rows from both tables; unmatched rows from either side have NULL values in the columns of the other table.

IBM Certification Practice Test