Participation constraints, Database Management System

Assignment Help:

The participation Constraints shows whether the existence of an entity depends on its being associated to another entity by the relationship type. There are two kinds of participation constraints:

Total: When the entire entities from an entity set participate in a relationship type, is known as total participation, for instance, the participation of the entity set student in the relationship set have to 'opts' is said to be total as each student enrolled must opt for a course.

Partial: When it is not necessary for all the entities from an entity set to partake in a relationship type, it is known as partial participation. For instance, the participation of the entity set student in 'represents' is partial, as not every student in a class is a class representative.


Related Discussions:- Participation constraints

Which operations need the participating relations to union, Which operation...

Which operations need the participating relations to be union compatible? A UNION, INTERSECTION and DIFFERENCE operations need the participating relations to be union compatibl

What is a view, What is a view?  Make a view of EMP table named DEPT 20, to...

What is a view?  Make a view of EMP table named DEPT 20, to display the employees in department 20 and their annual salary.  Ans:  View is a virtual table that does not consist

Logical operators-logical operators, Logical Operators Rules of Preced...

Logical Operators Rules of Precedence: Order evaluated Operator 1 All comparison operators 2

Database, How many physical thing?

How many physical thing?

Enumerate about the high-level transitions result, Show, with the help of a...

Show, with the help of an example, that relatively high-level transitions result when system or program is stimulated by the outside events. In diagram below, we can observe i

Self-join, Self-Join:   In a self join a table is joined with itself.  Let ...

Self-Join:   In a self join a table is joined with itself.  Let consider the following sample partial data of EMP table EMPNO ENAME MGRID

Write short note on data models, Write short note on Data models? Data...

Write short note on Data models? Data models: A data model is an abstract model which elaborates how data is represented and accessed. The term data model has two commonly ac

Define the query optimisation, Define the Query optimisation The query ...

Define the Query optimisation The query parser commonly generates a standard initial tree to correspond to an SQL query, with no doing any optimization. Such type of a canonica

Differences between a file processing system and a dbms, List any two signi...

List any two significant differences between a file processing system and a DBMS. File Processing System vs. DBMS Data Independence - Data independence is the capacity t

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