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 concurrency problems, Question: a) There are three concurrency...

Question: a) There are three concurrency problems, i.e. three types of potential mistake which could occur if concurrency control is not properly enforced in the database syst

Design of a database, Ask questioYou are the database administrator in a un...

Ask questioYou are the database administrator in a university. You have been tasked to come up with a new database for the University. Using the stages in Database Life Cycle come

Create student db and execute insert query, Create Student DB and execute I...

Create Student DB and execute Insert query? STUDENT (name, student#, class, major) COURSE (course name, course#, credit hours, department) SECTION (section identifier, course

What is hierarchical dbms, What is Hierarchical DBMS In HDBMS, data is ...

What is Hierarchical DBMS In HDBMS, data is structured in a tree like manner. There is a parent-child relationship between data items and the data model is very suitable for re

Mr.dattu, Define a job scheduling strategy that will meet business requirem...

Define 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 pictori

Oracle, List and explain the memory constructs of the Oracle 12c databases?...

List and explain the memory constructs of the Oracle 12c databases?

For known, What are the function of DBA?

What are the function of DBA?

Data models, why older data models are being replaced by new data models....

why older data models are being replaced by new data models.

Database backup, Discuss the importance and characteristics of database bac...

Discuss the importance and characteristics of database backup and recovery procedures, then describe the actions that must be detailed in backup and recovery plan

Define thomas write rule, Define Thomas write rule Thomas' write rule: ...

Define Thomas write rule Thomas' write rule: The Thomas' write rule is a modification of timestamp-ordering protocol for concurrency control. Assume that transaction T i issue

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