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

Define the third normal form, Define the Third Normal Form: The third ...

Define the Third Normal Form: The third normal form (3NF) is a normal form employed in database normalization. 3NF was initially defined by E.F. Codd in 1971. Codd's definitio

Define atomicity and aggregation, Atomicity : Either all functions are lai...

Atomicity : Either all functions are laid out or none are. Users could not have to think about the effect of incomplete operations. DBMS ensures this by undoing the functions

What is multivalued attribute, What is Multivalued Attribute? Multival...

What is Multivalued Attribute? Multivalued Attribute - Multivalued attribute might have more than one value for an entity. For instance, PreviousDegrees of a STUDENT.

List the sql domain types, List the SQL domain Types? SQL supports the ...

List the SQL domain Types? SQL supports the following domain types. 1) Char(n) 2) varchar(n) 3) int 4) numeric(p,d) 5) float(n) 6) date.

Objectives-transactions and concurrency management, Objectives After Re...

Objectives After Reading this part, you should be able to: Explain the term CONCURRENCY; Describe the term transaction and concurrent transactions; Talk about co

List the data structures implemented by the storage manager, List the data ...

List the data structures implemented by the storage manager. The storage manager executes the following data structure a) Data files b) Data dictionary c) indices

Explain the concept of deadlock, Explain the concept of deadlock Yes. I...

Explain the concept of deadlock Yes. It can direct to deadlock. Suppose that a batch of frames arrived correctly and were accepted. Then receiver will advance its window. Now s

What is structured query langauge, What is Structured Query Langauge (SQL)?...

What is Structured Query Langauge (SQL)? SQL is a powerful set-oriented language which was formed by IBM research for the databases that adhere to the relational model. It havi

On laod, how to write a in a text and load it on mysql

how to write a in a text and load it on mysql

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