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 is log shipping, What is Log Shipping? Log shipping is the method ...

What is Log Shipping? Log shipping is the method of automating the backup of database and transaction log files on a production SQL server, and then restoring them onto a stand

What are the technique to define a schema completely, What are the techniqu...

What are the technique to define a schema completely ? A schema is completely define by DDL and DML query language.

Define the term- making common behaviour abstract, Making Common Behaviour ...

Making Common Behaviour Abstract Let us define abstraction "Abstraction means to focus on the necessary, inherent aspects of an entity and ignoring its accidental features". O

Define catalog and meta data, Define Catalog and meta data ? A catalog ...

Define Catalog and meta data ? A catalog is a compilation of records elaborating the contents of a particular collection or group of collections. Metadata (Meta data, or someti

What is the meaning of data independence, What is the meaning of Data indep...

What is the meaning of Data independence? Data independence means a programs that are not dependent on the physical attributes of data and a programs that are not dependent on

Mention the various user privileges, Mention the various user privileges ...

Mention the various user privileges All privileges directly granted to the user or role. All privileges granted to roles that have been granted to the user or role.

Describe the types of inheritance, Describe the types of Inheritance ...

Describe the types of Inheritance 1.  Single inheritance 2.  Multiple inheritance 3.  Hierarchical inheritance 4.  Multilevel inheritance

Two types of blocks in the fixed -length representation, What are the two t...

What are the two types of blocks in the fixed -length representation? Define them. Anchor block: Have the first record of a chain. Overflow block: Have the records other tha

What is 2nf, What is 2NF? A relation schema R is in 2NF if it is in 1NF...

What is 2NF? A relation schema R is in 2NF if it is in 1NF and every non-prime attribute A in R is fully functionally dependent on primary key.

B-tree, construct a b-tree for the following set of key values 2,3,5,7,11,1...

construct a b-tree for the following set of key values 2,3,5,7,11,17,19,23,29,31.assume that the tree is initial empty and the values are added in ascending order

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