Which statement is true regarding constraints、

试卷相关题目

• 1Which type of constraint can be used to ensure that an INTEGER column in a table will never be assigned more than one record that contains a NULL value、

  A.Unique constraint

  B.Primary key constraint

  C.Informational constraint

  D.Column default constraint

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• 2Which is NOT a valid reason for creating an index、

  A.To allow queries to run more efficiently.

  B.To enforce constraints such as uniqueness on index keys.

  C.To order the columns of a table in ascending or descending sequence according to values in a row.

  D.To order the rows of a table in ascending or descending sequence according to the values in a column.

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• 3By default, a column defined as a TIMESTAMP includes which attributes、

  A.No fractional digits or time zone.

  B.6 fractional digits and no time zone.

  C.12 fractional digits plus a time zone.

  D.12 fractional digits and no time zon

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• 4What is the primary purpose of a view、

  A.To enable uniqueness.

  B.To ensure data clustering.

  C.To combine data from multiple tables.

  D.To optimize queries ran against multiple tables.

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• 5Which two statements are true about foreign key constraints、 (Choose two.)

  A.The foreign key constraint columns must be supported by an index.

  B.The foreign key constraint columns must be defined as NOT NULL.

  C.The number and data types of foreign key constraint columns must match the parent key.

  D.The columns of one foreign key constraint cannot be used in another foreign key constraint.

  E.To define a foreign key constraint there must be an associated primary key or unique key in the same or different table.

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• 6By default, where is the data stored for a column defined with an XML data type、

  A.In an XML index.

  B.In line with the rest of the data for the table.

  C.In an XML storage object that is separate from the table.

  D.In line with the rest of the data for the table, for XML columns less than 32KB.

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• 7Which statement about BEFORE triggers is FALSE、

  A.A BEFORE trigger can be used to perform validation of input data.

  B.A BEFORE trigger can be used to automatically generate values for newly inserted rows.

  C.A BEFORE trigger is fired for each row in the set of affected rows before the trigger event executes.

  D.A BEFORE trigger is fired for each row in the set of affected rows instead of executing the trigger event.

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• 8What is used in conjunction with a foreign key to define a relationship between two tables、

  A.Primary key

  B.Partitioning key

  C.Check constraint

  D.Unique constraint

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• 9Which case will require a sequence to be dropped and recreated instead of being modified by the ALTER SEQUENCE statement、

  A.Change the data type of the sequence.

  B.Reset the sequence to its starting value.

  C.Establish new minimum or maximum values.

  D.Change the increment between future values.

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• 10Given the following statement:GRANT DELETE ON TABLE sales TO User1 WITH GRANT OPTION;Which statement is correct、

  A.USER1 can only remove the SALES table.

  B.USER1 can only remove records from the SALES table.

  C.USER1 can remove the SALES table and grant the privilege to remove the SALES table to other users.

  D.USER1 can remove records from the SALES table and grant the privilege to remove records from the SALES table to other users.

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