Define entity integrity and referential integrity, Database Management System

Assignment Help:

Define entity integrity and referential integrity.  How does SQL allow specification of  these?

Ans: Entity Integrity Rule- If the attribute A of relation R is a prime attribute of R after that A cannot accept null values. 

Referential Integrity Rule- In referential integrity, it is made sure that a value that appears in one relation for a given set of attributes as well appears for a particular set of attributes in another relation.

 In SQL, referential integrity and entity integrity rules are implemented as constraints on the relation known as reference Key constraint and primary Key constraint correspondingly.

 These constraints can be fixed with relation at the time of creation of the relations or after the creation of the relations by altering the definition of the relations. For instance:

 

600_Define entity integrity and referential integrity.png

 


Related Discussions:- Define entity integrity and referential integrity

Explain discretionary access control, Problem: (a) Given the following ...

Problem: (a) Given the following relation: Stats(Name,Sex,Children, Occupation, Salary, Tax, Audits) Write SQL code to define the following security constraints: (i) User

List the types of authorization, List the types of authorization. A) R...

List the types of authorization. A) Read authorization B) Write authorization C) Update authorization D) Drop authorization

Data management, Develop a database broker framework to implement a persist...

Develop a database broker framework to implement a persistence mechanism for the domain objects involved in the use case dealt with in Question 2.  a. Specify the attribute type

Define 3nf normal form, 3NF Normal Form A relation schema R is in 3NF ...

3NF Normal Form A relation schema R is in 3NF if it is in 2NF and for each FD X A either of the following is true X is a Super-key of R. A is a prime attribute of R

Relationship, What is multiple relationship ?

What is multiple relationship ?

Convert encrypted hsql database into csv format, Project Description: We...

Project Description: We have an encrypted HSQL Database which we want to change into csv format. HSQL DB . We have java application (jar file) which reads that database but n

Explain two phase locking protocol, Explain Two phase locking protocol ...

Explain Two phase locking protocol A transaction is consider as to follow the two-phase locking protocol if all locking operations precede the first unlock operation in the tra

Data warehouse, #queDefine a job scheduling strategy that will meet busines...

#queDefine 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 pic

File Management Principles, What are the requirements to ensure the objecti...

What are the requirements to ensure the objectives of file management principle is realized?

#cursor, #what is cursor its uses ? Explain it

#what is cursor its uses ? Explain it

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