Database Mod 8 Practice Quiz

Which of the following statements about creating constraints is incorrect?​ A)If a constraint applies to more than one column, the constraint must be created at the table level. B)Using the column level approach, the definition of the constraint is included as part of the column definition. C)When you create constraints at the column level, the constraint being created applies to the column specified. D)The NOT NULL constraint can be created at either the column level or the table level.

The NOT NULL constraint can be created at either the column level or the table level.

A constraint is always enforced at the table level. True False

True

A(n) FOREIGN KEY constraint is used to ensure that referential integrity exists between tables. True False

True

The ADD clause of the ALTER TABLE command is used to add a PRIMARY KEY constraint to an existing table.

True

Which view will display the names of all the constraints that you own? A)DISPLAY_CONSTRAINTS B)ALL_CONSTRAINTS C)USER_CONSTRAINTS D)TABLE_CONSTRAINTS

USER_CONSTRAINTS

If a PRIMARY KEY constraint, named ORDERITEMS_PK, exists for the ORDER# and ITEM# columns of the ORDERITEMS table, which of the following commands will disable the constraint?​ A)ALTER TABLE orderitems DISABLE PRIMARY KEY CONSTRAINT; B)ALTER TABLE orderitems DISABLE CONSTRAINT orderitems_pk; C)ALTER TABLE orderitems REMOVE PRIMARY KEY CONSTRAINT; D)​ALTER TABLE orderitems MODIFY PRIMARY KEY CONSTRAINT DISABLE;

ALTER TABLE orderitems DISABLE CONSTRAINT orderitems_pk;

Which clause will allow you to disable a constraint? A)MODIFY B)DROP C)DISABLE D)STOP

DISABLE

Which of the following statements about creating constraints is incorrect?​ A)​If you do not provide a name for a constraint, the Oracle 12c server will issue an error message. B)There are two approaches for creating constraints: at the column level or the table level. C)One industry convention is to use the format tablename_columnname_constraint type for the constraint name. D)​none of the above

If you do not provide a name for a constraint, the Oracle 12c server will issue an error message.