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

Schema, difference between internal schema and external schema in DBMS

difference between internal schema and external schema in DBMS

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

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

Describe in brief about object oriented design, Describe about Object orien...

Describe about Object oriented design Object oriented design is concerned with developing an object oriented model of a software system to implement known requirements. Many OO

Define database layer, Define Database layer? The database layer define...

Define Database layer? The database layer defines the data formats used in the database.

State the meaning of object representation, State the meaning of Object Rep...

State the meaning of Object Representation  The term object representation means "to represent object with the help of objects model symbols". Implementing objects is too simp

Er diagram, a publishing company produce scientific books on various subjec...

a publishing company produce scientific books on various subjects. the books are written by authors who specialize in one particular subject. the company employs editors who, not n

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

Explain the 10 reasons to use mysql, Question 1 Explain the 10 reasons to ...

Question 1 Explain the 10 reasons to use MySQL Question 2 Write the SQL statements to demonstrate the following using SELECT command Expression Evaluation ORDER BY

Implementation of integrity rules, Question 1 Describe the following- ...

Question 1 Describe the following- Clustering Indexing Question 2 Explain the following with suitable real time examples- Implementation of Integrity rules

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