单选题Which of the following is true of an index used to support a UNIQUE constraint?（）A It must have the UNIQUE attribute.B It cannot be created explicitly by the user.C It must have the UNIQUE and CLUSTER attributes.D It must have the UNIQUE WHERE NOT NULL

题目

单选题

Which of the following is true of an index used to support a UNIQUE constraint?（）

It must have the UNIQUE attribute.

It cannot be created explicitly by the user.

It must have the UNIQUE and CLUSTER attributes.

It must have the UNIQUE WHERE NOT NULL attribute.

更多“单选题Which of the following is true of an index used to support a UNIQUE constraint?（）A It must have the UNIQUE attribute.B It cannot be created explicitly by the user.C It must have the UNIQUE and CLUSTER attributes.D It must have the UNIQUE WHERE NOT NULL”相关问题

第1题

While designing your database， you have created the EMPLOYEES table as an index-organized table （IOT）. You want to create a bitmap index on the JOB_ID column to make queries faster. Which task must have been completed so that you are able to create the bitmap index？（） A、A primary key must have been created.B、A mapping table must have been created.C、An overflow tablespace must have been specified.D、The PCTTHRESHOLD option must have been specified.

点击查看答案
第2题

A UDT is a data type which:（）A、must contain unique values.B、cannot be CAST to other data types.C、is created using the CREATE DISTINCT command.D、contains a value that was automatically calculated from values in other columns.

点击查看答案
第3题

which one of the following accurately describes field names?（）A、they must be unique in a database B、they can only be used once in a view C、they can only used once on each form D、they can be used mulriple times on a form

点击查看答案
第4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.

点击查看答案
第5题

Evaluate the CREATE TABLE statement： CREATE TABLE products （product_id NUMBER （6） CONSTRAINT prod_id_pk PRIMARY KEY， product_name VARCHAR2 （15））； Which statement is true regarding the PROD_ID_PK constraint？（）A、 It would be created only if a unique index is manually created first.B、 It would be created and would use an automatically created unique index.C、 It would be created and would use an automatically created nonunique index.D、 It would be created and remains in a disabled state because no index is specified in the command.

点击查看答案
第6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.

点击查看答案
第7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.

点击查看答案

单选题Which of the following is true of an index used to support a UNIQUE constraint?（）A It must have the UNIQUE attribute.B It cannot be created explicitly by the user.C It must have the UNIQUE and CLUSTER attributes.D It must have the UNIQUE WHERE NOT NULL

题目

更多“单选题Which of the following is true of an index used to support a UNIQUE constraint?（）A It must have the UNIQUE attribute.B It cannot be created explicitly by the user.C It must have the UNIQUE and CLUSTER attributes.D It must have the UNIQUE WHERE NOT NULL”相关问题

第1题

第2题

第3题

第4题

第5题

第6题

第7题

相关内容