Creating views with check option-data control, Database Management System

Assignment Help:

Creating views with check option: This option limits those updates of data values that cause records to go off the view. The following instance tells this in more detail:

Example: To produce a view for employees of Department = 30, such that user cannot alter the department number from the view:

CREATE OR REPLACE VIEW EMPD30 AS

SELECT EMPNO EMPL_NUM, ENAME NAME, SAL SALARY FROM EMP

WHERE DEPTNO=30

WITH CHECK OPTION;

 

Now the user cannot alter the department number of any record of view EMPD30. If this change is permitted then the record in which the change has been made will go off the view as the view is only for department-30. This restricted due to use of WITH CHECK OPTION clause

 


Related Discussions:- Creating views with check option-data control

Vertical fragmentation, Vertical Fragmentation- Vertical fragmentation grou...

Vertical Fragmentation- Vertical fragmentation groups together only those attributes in a relation that are used jointly by various important transactions. A vertical fragment is d

Briefly describe concurrency execution, Briefly describe concurrency execut...

Briefly describe concurrency execution? Lock - based protocols Locks There are several modes in which a data item may be locked in this section we restrict our attention

Physical model of traffic data management, After the completion of the logi...

After the completion of the logical model the physical model is to be made. The oracle 10 G will be used as a database server and all the tables with their column are created and i

Forward recovery (redo), Forward Recovery (Redo): In this system the commit...

Forward Recovery (Redo): In this system the committed changes made by a transaction are reapplied to a previous copy of the database.                          In simpler

In the architecture of a database system which external leve, In the archit...

In the architecture of a database system which external level used? In the architecture of a database system view external level used.

Express types of information available in mysql, Express types of informati...

Express types of information available in MySQL? Information as regards the result of queries:  This includes number of records affected by any SELECT or UPDATE or DELETE st

Basics of relational models, In the first unit of this block, you have been...

In the first unit of this block, you have been given with the details of the Database Management System, its structure, advantages etc. This unit is an attempt to give you informat

Name the various privileges in sql, Name the various privileges in SQL? ...

Name the various privileges in SQL? A) Delete B) Select C) Insert D) Update

What is average response time, What is average response time? The avera...

What is average response time? The average response time is that the average time for a transaction to be done after it has been submitted.

Case tools, explain at least five widly used case tools

explain at least five widly used case tools

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd