Describes the several relationship constraints, Database Management System

Assignment Help:

Describes the several relationship constraints through giving suitable example?

Constraints on relationships: There are two kinds of constraints on relationships.

1) Mapping cardinalities or cardinality ratios express the number of entities to that another entity can be associated through a relationship set. For a binary relationship set among entities A and B. The mapping cardinality may be any one of the subsequent:

a) One to One: An entity in A is related along with at most one entity in B and an entity in B is related with at most one entity in A.
b) One to Many: An entity in A can be related with any number in B but an entity in B is associated with at most one in A.
c) Many to one: An entity in A is related with at most one in B but an entity in B is associated with any number in A.
d) Many to Many: An entity in A and B can be associated along with any number of entities in the other entity set.

2) Participation constraints: The participation of an entity set E in a relationship set R is said to be total if every entity in E participates within at least one relationship in R. If only a few entities in E participation of entity set E in relationship R is said to be partial.


Related Discussions:- Describes the several relationship constraints

Dbms, You are managing the following database system: • DBMS: Oracle 11g ...

You are managing the following database system: • DBMS: Oracle 11g • OS: Sun Solaris • System architecture: Web-based application using ASP.Net • Purpose of Server: HR managem

Write the motivations led to development of oo-dbms, Write the motivations ...

Write the motivations led to development of OO-DBMS? 1.  Programmer frustration with RDBMSs. 2.  Requirement for special features.

Special workarea for interface, While using extract datasets it is required...

While using extract datasets it is required to have a special workarea for interface False.  It is not required to have a special workarea for interface

Er database theoretical and modeling database system, Need an expert in ER ...

Need an expert in ER database theoretical and modeling database system Project Description: Need an expert in ER database theoretical and modeling database systems? Skills

Describe the advantage of state chart diagram, Describe the advantage of St...

Describe the advantage of State chart Diagram A state chart represents a state machine, emphasizing flow of control from one state to other. A state machine is a behaviour whi

How can you terminate the mysql server, How can you terminate the MySQL Ser...

How can you terminate the MySQL Server? Typing the following in Command prompt will shut down the server completely as root user % mysqladmin -u root -p shutdown

Create student db and retrieve all student name in cs, Create a Student dat...

Create a Student database and Retrieve the names of all students majoring in ‘CS' Consider the following relational database: STUDENT (name, student#, class, major) COURSE (co

In an e-r diagram an entity set is represent by, In an E-R diagram an entit...

In an E-R diagram an entity set is represent by? In an E-R digram entity set is represted by rectangle.

Partial relation emp-get the details people with min salary, Let consider t...

Let consider the given partial relation EMP. Let us make some sub-queries for them EMPNO ENAME JOB SAL DEPTNO 7566

Mention constraints to create command ddl, Mention the type of constraints ...

Mention the type of constraints we can specify in the CREATE command of DDL. The type of constraints that can be specified are as follows:- PRIMARY KEY, NOT NULL, UNIQUE, FOR

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