Determine the strong and weak entity, Database Management System

Assignment Help:

Determine the Strong and Weak Entity

Based on the method of foreign key, there might be arise a situation when we have to relate an entity having a primary key of its own and an entity not having a primary key of its own. In such a case, the entity having its own primary key is known as a strong entity and the entity not having its own primary key is known as a weak entity. Whenever we need to relate a strong and a weak entity together, the ERD would alter just a little.

Say, for instance, we have a statement "A Student lives in a Home." STUDENT is obviously a strong entity having a primary key Roll. But HOME might not have a unique primary key, as its only attribute Address may be shared by a lot of homes (what if it is a housing estate?). HOME is a weak entity in this case.

 


Related Discussions:- Determine the strong and weak entity

Objectives of database manangement system, OBJECTIVES After going thro...

OBJECTIVES After going through this unit you should be capable to: Explain the File Based system and its limitations; Explain the structure of DBMS; Explain the

Management information system, Explain the challenges before an E-business ...

Explain the challenges before an E-business management.

Give a sample of the dynamic model, Give a sample of the Dynamic Model. ...

Give a sample of the Dynamic Model. The sample of dynamic model is given below:  Dynamic model for the car: Brake and Accelerator            Brake or Applies Accelerator

Functional dependencies, 1. Staff (staffID --> availabilityID) 2. Servic...

1. Staff (staffID --> availabilityID) 2. Services (servicesID --> itemBasedID --> timedBasedID) 3. TimedBased (timedbasedID--> priceid) 4. Clients (clientId, serviceId-->

What are the properties in a relation, What are the properties in a relatio...

What are the properties in a relation ? In a relation Ordering of rows is immaterial and No two rows are identical.

Describe query evaluation engine, Describe Query evaluation engine? Que...

Describe Query evaluation engine? Query Evaluation engine: Vehicle executes low-level instructions obtained through the DML compiler. The Storage Manager Components gives in

Distributed Database query processing , I am doing research in this area, e...

I am doing research in this area, especially in sime join and join efficacy when several relations have been queried. Relations located in different sites. I need something like n

Query optimization in database system, Problem : AirwaysCentre, an inte...

Problem : AirwaysCentre, an international airline booking company currently uses a relational database system for their operations, which includes the following relations: P

Differentiate between a global and a local temporary table, Differentiate b...

Differentiate between a Global and a Local temporary table? - A local temporary table exists only for the duration of a connection or if defined inside a compound statement, fo

Describe parameteric end users, Describe Parameteric end users? Paramet...

Describe Parameteric end users? Parametric end users might be given update access, but are commonly not permitted to change the structure of data.

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