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

What is the state machine engine, What is the State Machine Engine The...

What is the State Machine Engine The straightest approach to implement control is to have any way of explicitly representing and executing state machines. With the help of thi

What are the several forms of identity, What are the several forms of ident...

What are the several forms of identity? a) Value b) Name c) Built-in

Idea for fyp, want a idea for final year project

want a idea for final year project

Process of adjustment of inheritance, Process of Adjustment of inheritance ...

Process of Adjustment of inheritance During object design, inheritance is readjusted by rearranging classes and operations, and abstracting common behaviour.

Convert encrypted hsql database into csv format, Project Description: We...

Project Description: We have an encrypted HSQL Database which we want to change into csv format. HSQL DB . We have java application (jar file) which reads that database but n

What is a transaction? , What is a transaction ? The Transaction is a un...

What is a transaction ? The Transaction is a unit of data processing. For instance, many of the transactions at a bank may be withdrawal or deposit of money; transfer of money f

Data files indices and data dictionary, The indices are accumulated in the ...

The indices are accumulated in the index files. The data is accumulated in the data files. Indices give fast access to data items. For example, a book database may be managed in th

Database administrator, Database Administrator One of the main perpos...

Database Administrator One of the main perpose for having the database management system is to have control of both data or programs accessing that data. The person having li

Normalization, a project based on normalization with first, second and thir...

a project based on normalization with first, second and third normalization. There need to be a diagram also

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