你可能感興趣的試題

單項選擇題

The ST_INFO master table has millions of rows that are updated very rarely. It has a STATE_CODE column that contains the value for 25 states. The table is frequently queried on the STATE_CODE column.
Which type of index would you suggest to improve the query performance？（）

A.Btree
B.bitmap
C.reverse key
D.function based

多項選擇題

A constraint in a table is defined with the INITIALLY IMMEDIATE clause. You executed the ALTER TABLE command with the ENABLE VALIDATE option to enable the constraint that was disabled. What are the two effects of this command？（）

A.It fails if any existing row violates the constraint.
B.It does not validate the existing data in the table.
C.It enables the constraint to be enforced at the end of each transaction.
D.It prevents insert， update， and delete operations on the table while the constraint is in the process of being enabled.

Which two are valid locking levels that are used by transactions in an Oracle database？（）

你可能感興趣的試題

The ST_INFO master table has millions of rows that are updated very rarely. It has a STATE_CODE column that contains the value for 25 states. The table is frequently queried on the STATE_CODE column. Which type of index would you suggest to improve the query performance？（）

A constraint in a table is defined with the INITIALLY IMMEDIATE clause. You executed the ALTER TABLE command with the ENABLE VALIDATE option to enable the constraint that was disabled. What are the two effects of this command？（）

Which two are valid locking levels that are used by transactions in an Oracle database？（）

The ST_INFO master table has millions of rows that are updated very rarely. It has a STATE_CODE column that contains the value for 25 states. The table is frequently queried on the STATE_CODE column.
Which type of index would you suggest to improve the query performance？（）