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

Describe dynamic model, Describe Dynamic Model. The dynamic model speci...

Describe Dynamic Model. The dynamic model specifies allowable sequences of changes to the objects from an object model. It contains event trace diagrams describing scenarios. A

Assign, #quesDefine a job scheduling strategy that will meet business requi...

#quesDefine a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pi

Explain the deferred update, Explain the Deferred Update The deferred ...

Explain the Deferred Update The deferred update methods do not physically update the database on disk till after a transaction reaches its commit point; after that the updates

In an e-r diagram how attributes are represented, In an E-R diagram how att...

In an E-R diagram how attributes are represented ? In an E-R diagram attributes are represented in a ellipse.

Locks, Locks: Serialisabilty is just a test whether a given interleaved sch...

Locks: Serialisabilty is just a test whether a given interleaved schedule is ok or has a concurrency related trouble. Though, it does not make sure that the interleaved concurrent

Explain the term high level dml, Explain the term High level DML? High...

Explain the term High level DML? High level DML A high-level or non-procedural DML permit the user to specify what data is needed without specifying how it is to be acquired.

Create an index for the table client, Create an index for the table Client,...

Create an index for the table Client, field CLIENT_NO of Q ? Command:   CREATE INDEX client_client_no ON client(client_no);

Wait-die scheme -deadlock prevention, Wait-die" scheme : The idea is based ...

Wait-die" scheme : The idea is based on non-preventive method. It is based on a simple rule:                                 If Ti requests a database resource that is held by T

Explain about primary key, Explain about primary key Primary Key: It ...

Explain about primary key Primary Key: It is one of the candidate keys that are taken to be the recognizing key for the entire table. E.g. although there are two candidate ke

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