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

horizontal fragmentation, Horizontal Fragmentation- Horizontal fragmentati...

Horizontal Fragmentation- Horizontal fragmentation groups together the tuples in a relation that are collectively used by the main transactions. A horizontal fragment is produced b

Which is the properties of entities, Which is the properties of entities? ...

Which is the properties of entities? Attributes is the properties of entities.

Name the various privileges in sql, Name the various privileges in SQL? ...

Name the various privileges in SQL? A) Delete B) Select C) Insert D) Update

Queries, Write a query that display ename annual salary and comm from emp t...

Write a query that display ename annual salary and comm from emp table

Project, Preliminary entities and attributes of human resourse management d...

Preliminary entities and attributes of human resourse management database management system

What database management system, Company XYZ is an advertising company. It...

Company XYZ is an advertising company. It has its own website but the search facilities offered are not reliable. The company is willing to invest to acquire new machines and sof

State the technique for converting a state diagram to code, Q. State the Te...

Q. State the Technique for converting a state diagram to code. i) Identify the major control path. Starting with first state, find the path from diagram that corresponds

What is predictive modelling, Problem: (a) Data mining is one of the b...

Problem: (a) Data mining is one of the best ways to analyse data and using software techniques, hidden and unexpected patterns and relationships in sets of data can be extrac

Deletion anomalies-data redundancy, Deletion Anomalies: Loss of important ...

Deletion Anomalies: Loss of important Information: In some cases, useful information may be lost when a tuple is deleted. For instance, if we delete the tuple corresponding to stu

Construct an er diagram for a hospital, Construct an ER diagram for a hospi...

Construct an ER diagram for a hospital along with a set of patients and a set of medical doctors Associate with every patient a log of the several tests and examinations conducted.

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