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

What are the various symbols used to draw an e-r diagram, What are the vari...

What are the various symbols used to draw an E-R diagram? Explain with the help of an example how weak entity sets are represented in an E-R diagram. Various symbols used to d

Multi-key file organisation, Multi-Key File Organisation In this part, ...

Multi-Key File Organisation In this part, we will introduce two basic file Organisation schemes that permit records to be accessed by more than one key field, therefore, allowi

Nested relational model, what is Nested relational model? Explain with exam...

what is Nested relational model? Explain with examples.

Which of the operations constitute a basic set of operations, Which of the ...

Which of the operations constitute a basic set of operations for manipulating relational data? Relational algebra operations constitute a basic set of operations for manipulati

Clustering indexes, Clustering Indexes It may be an excellent idea to k...

Clustering Indexes It may be an excellent idea to keep data of the students in the order of the programme they have registered as most of the data file accesses may need studen

Consistency-transaction , Consistency: This property makes sure that a com...

Consistency: This property makes sure that a complete transaction implementation takes a database from one consistent state to another consistent state. If the transaction fails e

Produce a set of relations - normalisation, Produce a set of relations (equ...

Produce a set of relations (equivalent to the Finkelstein entity list) in third normal form (3NF) from the following un-normalised relation. You must use the Finkelstein methodolog

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