Explain entity integrity and referential integrity rules, Database Management System

Assignment Help:

Explain entity integrity and referential integrity rules within relational model. Show how these are realized in SQL?

Entity Integrity Rule - No primary key value could be null.

Referential Integrity Rule - In referential integrity, it is ensured in which a value which appears in one relation for a given set of attributes also appears for a certain set of attributes within another relation.

In SQL, entity integrity and referential integrity rules are implemented as constraints on the relation known as primary key constraint or reference key constraint corresponding. These constraints can be specified along with relation at the time of creation of the relations or after the creation of the relations through altering the definition of the relations. For instance:

CREATE TABLE DEPT

(DEPTNO NUMBER PRIMARY KEY,

DNAME VARCHAR2(15));

CREATE TABLE EMP

(EMPNO NUMBER PRIMARY KEY,

 20

 ENAME VARCHAR2(15),

JOB VARCHAR2(10),

DEPTNO NUMBER REFERENCES DEPT(DEPTNO));


Related Discussions:- Explain entity integrity and referential integrity rules

Write a short note on qbe, Write a short note on QBE? Stands for "Quer...

Write a short note on QBE? Stands for "Query By Example." QBE is a feature involved along with various database applications which gives user-friendly techniques of running da

Explain the operation of the data warehouse, Using a labelled diagram expla...

Using a labelled diagram explain the operation of the Data Warehouse, define the basic architectural components and outline the main functionalities. Briefly explain the role an op

Graphical user interface tools, These are interactive interfaces, graphical...

These are interactive interfaces, graphical that hide the difficulty of the DBMS and query language behind an intuitive, simple to understand, and convenient interface. This permit

Money making supermarket chain problem, Consider the ER schema below for th...

Consider the ER schema below for the MoneyMaking supermarket chain problem. Translate the given ER schema into SQL CREATE TABLE statement.

Give concurrent sub states diagram for the classroom, Give Concurrent sub s...

Give Concurrent sub states diagram for the classroom and exam held. In Figure, simultaneous substrates have been taken. After passing Minor 1 test you could give Minor 2 test. T

What is advantage of two-way association, What is advantage of two-way asso...

What is advantage of two-way association? Two-way association advantages are following: a) Independent of the classes. b) Useful for existing predefined classes that are

Describe the responsibilities of the dba and the database, Describe the res...

Describe the responsibilities of the DBA and the database designer ? The responsibilities of DBA and database designer are: 1. Planning for the database's future storage needs

State the object design for processing, State the Object Design for Process...

State the Object Design for Processing  The object design phase comes after analysis and system design phase. The object design phase includes implementation details like as i

What are the advantages of logical databases, What are the advantages of Lo...

What are the advantages of Logical Databases? It offers a simple-to-use selection screens.  You can change the pre-generated selection screen to your needs.  It offers check f

Write short notes on relational model, Write short notes on relational mode...

Write short notes on relational model The relational model uses a collection of tables to show both data and the relationships between those data. The relational model is an ex

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