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

Differentiate between procedural and non procedural language, Differentiate...

Differentiate between Procedural and non procedural languages ? Procedural and non procedural languages - A procedural language specifies the operations to be performed on th

Describe all integrity constraints which are violated, Consider the two rel...

Consider the two relations given below Given that A is the primary key of R, D is the primary key of S and there is a referential integrity among S.A and R.A, discuss all

Prepare a data flow diagram for computing the volume, Prepare a data flow d...

Prepare a data flow diagram for computing the volume and surface area of a cylinder. Inputs are the height and radius of the cylinder. Outputs are the volume and surface area of th

Define the wait for graph, Define the Wait for graph Ans: The wait-for-...

Define the Wait for graph Ans: The wait-for-graph is a directed graph and consist of nodes and directed arcs; the nodes of the graph are active transactions. An arc of the grap

Draw an er diagram for organization of a student database, Draw an ER diagr...

Draw an ER diagram that shows the organization of a simple student database. The database captures the information about letter grades obtained by university students who enrolled

What are the situations while dbms should not be used, What are the situati...

What are the situations while DBMS should not be used? DBMS should not be used in situations like: (i) No need of security. (ii) Not difficulty to access the data (iii) N

Help, #questiononsider the following relation: CAR_SALE =(CAR_ID,oPTION_TYP...

#questiononsider the following relation: CAR_SALE =(CAR_ID,oPTION_TYPE, Option_listpreice, Sale_date, Option_discountedprice)..

Describe embedded query language, Describe Embedded Query Language? Emb...

Describe Embedded Query Language? Embedded Query Language - A query language (e.g., SQL) can be implemented in two ways. It can be used interactively or embedded within a host

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