Which two statements about creating constraints are true?（）A、Constraint names must start with SYS_CB、All constraints must be defines at the column levelC、Constraints can be created after the table is createdD、Constraints can be created at the same time th

题目

Which two statements about creating constraints are true?（）

A、Constraint names must start with SYS_C
B、All constraints must be defines at the column level
C、Constraints can be created after the table is created
D、Constraints can be created at the same time the table is created
E、Information about constraints is found in the VIEW_CONSTRAINTS dictionary view

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第1题：

When defining a referential constraint between the parent table T2 and the dependent table T1, which of the following is true?（）

A、The list of column names in the FOREIGN KEY clause can be a subset of the list of column names in the primary key of T2 or a UNIQUE constraint that exists on T2.
B、The list of column names in the FOREIGN KEY clause can be a subset of the list of column names in the primary key of T1 or a UNIQUE constraint that exists on T1.
C、The list of column names in the FOREIGN KEY clause must be identical to the list of column names in the primary key of T2 or a UNIQUE constraint that exists on T2.
D、The list of column names in the FOREIGN KEY clause must be identical to the list of column names in the primary key of T1 or a UNIQUE constraint that exists on T1.

正确答案:C

第2题：

Which two statements are true about constraints? （）

A、The UNIQUE constraint does not permit a null value for the column.
B、A UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.
C、The PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.
D、The NOT NULL constraint ensures that null values are not permitted for the column.

正确答案:B,D

第3题：

What is true about updates through a view? ()

A. You cannot update a view with group functions.

B. When you update a view group functions are automatically computed.

C. When you update a view only the constraints on the underlying table will be in effect.

D. When you update a view the constraints on the views always override the constraints on the underlying tables.

参考答案：A

第4题：

Which statements are true regarding system-partitioned tables？（）

A、 Only a single partitioning key column can be specified.
B、 All DML statements must use partition-extended syntax.
C、 The same physical attributes must be specified for each partition.
D、 Unique local indexes cannot be created on a system-partitioned table.
E、 Traditional partition pruning and partitionwise joins are not supported on these tables.

正确答案:D,E

第5题：

Examine the command that is used to create a table： SQL> CREATE TABLE orders（oid NUMBER（6） PRIMARY KEY， odate DATE， ccode NUMBER（6）， oamt NUMBER（10，2）） TABLESPACE users； Which two statements are true about the effect of the above command）（）

A、A CHECK constraint is created on the OID column.
B、A NOT NULL constraint is created on the OID column.
C、The ORDERS table is the only object created in the USERS tablespace.
D、The ORDERS table and a unique index are created in the USERS tablespace.
E、The ORDERS table is created in the USERS tablespace and a unique index is created on the OIDcolumn in the SYSTEM tablespace.

正确答案:B,D

第6题：

Which two statements are true regarding views?（）

A、A subquery that defines a view cannot include the GROUP BY clause
B、A view that is created with the subquery having the DISTINCT keyword can be updated
C、A view that is created with the subquery having the pseudo column ROWNUM keyword cannot be updated
D、A data manipulation language (DML) operation can be performed on a view that is created with the subquery having all the NOT NULL columns of a table

正确答案:C,D

第7题：

You execute this command to drop the ITEM table， which has the primary key referred in the ORDERtable： SQL> DROP TABLE scott.item CASCADE CONSTRAINTS PURGE； Which two statements are true about the effect of the command（）

A、No flashback is possible to bring back the ITEM table.
B、The ORDER table is dropped along with the ITEM table.
C、The dependent referential integrity constraints in the ORDER table are disabled.
D、The dependent referential integrity constraints in the ORDER table are removed.
E、The table definition of the ITEM table and associated indexes are placed in the recycle bin.

正确答案:A,D

第8题：

Examine the following commands for redefining a table with Virtual Private Database (VPD) policies:Which two statements are true about redefining the table?()

A. All the triggers for the table are disabled without changing any of the column names or column types in the table.

B. The primary key constraint on the EMPLOYEES table is disabled during redefinition.

C. VPD policies are copied from the original table to the new table during online redefinition.

D. You must copy the VPD policies manually from the original table to the new table during online redefinition.

参考答案：B, C

第9题：

What is true about updates through a view? （）

A、You cannot update a view with group functions.
B、When you update a view group functions are automatically computed.
C、When you update a view only the constraints on the underlying table will be in effect.
D、When you update a view the constraints on the views always override the constraints on the underlying tables.

正确答案:A

第10题：

Which two statements about views are true?（）

A、A view can be created as read only.
B、A view can be created as a join on two or more tables.
C、A view cannot have an ORDER BY clause in the SELECT statement.
D、A view cannot be created with a GROUP BY clause in the SELECT statement.
E、A view must have aliases defined for the column names in the SELECT statement.

正确答案:A,B

Which two statements about creating constraints are true?（）A、Constraint names must start with SYS_CB、All constraints must be defines at the column levelC、Constraints can be created after the table is createdD、Constraints can be created at the same time th

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