Which statement about foreign keys is true、

试卷相关题目

• 1What is a function of a table check constraint、

  A.To provide a method of avoiding duplicate entries for a column.

  B.To provide a method of ensuring a column's values are within a specific range.

  C.To ensure that XML columns are properly populated in an associated XML table space.

  D.To enforce relationships between tables by checking the existence of rows in one table against another.

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• 2When a user-defined function (UDF) is created and no schema is specified, what schema is used to store the UDF、

  A.The SYSIBM schema.

  B.The SYSFUN schema.

  C.A schema with the name of the UDF.

  D.A schema with the userid of the UDF definer.

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• 3A table named STATES has the following columns: STATE_CD, REGION_CD, and STATE_NAME.Which SQL statement will return the number of states in each region, ordered by number of states、

  A.SELECT state_cd, COUNT(*) FROM states ORDER BY COUNT(*);

  B.SELECT state_cd, COUNT(*) FROM states GROUP BY state_cd ORDER BY state_cd;

  C.SELECT region_cd, COUNT(*) FROM states GROUP BY state_cd ORDER BY COUNT(*);

  D.SELECT region_cd, COUNT(*) FROM states GROUP BY region_cd ORDER BY COUNT(*);

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• 4Given the following statements:  CREATE TABLE employee(empid INTEGER,info XML); INSERT INTO employee VALUES(1, '<employeesinfo>    <name>Joe Smith</name>    <department name="DB2">     <team>Development</team>    </department>  </employeeinfo>'); If the following XQuery statement is executed:  XQUERY  for $info in deb2-fn:xmlcolumn('EMPLOYEE.INFO')/employeeinfo  return $info/name What will be the result、

  A.Joe Smith

  B.Joe Smith

  C.Joe Smith>DB2

  D.Joe Smith

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• 5Which statement about UPDATE processing is FALSE、

  A.The UPDATE statement logs the before and after value of every column it modifies.

  B.A searched UPDATE is used to update one or more rows and a positioned UPDATE is used to update exactly one row.

  C.When the UPDATE statement modifies parent key columns, the value of corresponding foreign key columns are also modifie

  D.D. The UPDATE statement modifies the values of specified columns in the rows of a table, view, or underlying table(s) of a specified fullselect.

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• 6Which type of table is best suited for recording results from application data manipulation that is not required to be persistent、

  A.Base Table

  B.Temporal Table

  C.Transition Table

  D.Temporary Table

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• 7Which statement regarding referential integrity constraints is true、

  A.Multiple primary keys can be defined for a table.

  B.A foreign key can reference multiple primary keys.

  C.A primary key can be referenced by only one foreign key.

  D.Primary keys and foreign keys are used to define relationships.

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• 8Which database object provides an alternative way of describing data that exists in one or more base tables、

  A.Alias

  B.View

  C.Index

  D.Sequence

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• 9The WITH CHECK OPTION clause of the CREATE VIEW statement allows you to do which of thefollowing、

  A.Define a view on one or more tables or views.

  B.Revalidate all invalid objects that are referenced on a view's fullselect.

  C.Ensure that any inserted or updated rows conform to the definition of the view.

  D.Define a view that only consists of columns that have check constraints defined.

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• 10Which type of constraint can be used to tell the DB2 Optimizer that a parent-child relationship exists between two tables, but that the relationship is not enforced、

  A.Check

  B.Unique

  C.Referential

  D.Informational

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