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

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

Related Rates, All edges of a cube are expanding at a rate of 6 centimeters...

All edges of a cube are expanding at a rate of 6 centimeters per second. How fast is the surface area changing when each edge is (a) 2 centimeters and (b) 10 centimeters?

Create the logical database schema, 1.  Based on the dependency diagram, cr...

1.  Based on the dependency diagram, create a database whose tables are in at least 2NF, showing the dependency diagram for each table (as shown in class).  Label the types of depe

State the definition of association, State the definition of association ...

State the definition of association An association is a structural relationship which specifies that objects of one thing are connected with objects of another. In UML, asso

What do you mean by persistence, What do you mean by persistence? How you w...

What do you mean by persistence? How you will make your data persistent? Persistent data is the data, which has a longer lifetime than program which has created it. Enabling th

Differentiate between pl/sql functions and procedures, Oracle & Distributed...

Oracle & Distributed Databases 1. Differentiate between PL/SQL functions and procedures. 2. Draw the diagram of logical structure of oracle database and explain it in brief.

Generalization and specialization, design a generalization specialization h...

design a generalization specialization hierarchy for a motor vehicle sales company. the company sells motorcycles, passenger cars, vens and buses.

Create a view that finds the student name, Section A:  Use the following ta...

Section A:  Use the following tables to create a database called College.  Use SQL commands. Student stuid(primary) lastName firstName

Create a view containing name and number of department, Create a view emp_d...

Create a view emp_dep containing e_name and number of dependents from the tables employee and dependent of (i) CREATE VIEW emp_dept AS SELECT ename, COUNT(*) FROM employee, dep

Dbms, Retrieve the S&S In-Chapter Database (in Microsoft Access format) fro...

Retrieve the S&S In-Chapter Database (in Microsoft Access format) from the text's Web site (or create the tables in Table 4-5 in a relational DBMS product). Write queries to answer

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