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

When are two schedules said to be view equivalent, When are two schedules s...

When are two schedules said to be view equivalent?     Ans: Two schedules that is denoted as S and S' are said to be view equivalent if the subsequent three conditions are met

Sparse and dense indexes, Sparse and Dense Indexes These indexes in pri...

Sparse and Dense Indexes These indexes in principle are the similar as that of indexes used at the back of the book. The key facts of the indexes are: They are arranged

Please answer me., gyan gurukul is a software company that provides softwar...

gyan gurukul is a software company that provides software related solution.

What is a super key, What is a super key? A super key is a set of one o...

What is a super key? A super key is a set of one or more attributes that collectively permits us to recognize uniquely an entity in the entity set.

Find the employee name, Example -Find the employee name, salary, department...

Example -Find the employee name, salary, department number and average salary of his/her department, for those employees whose salary is more than the average salary of that depart

Produce a logical database design for pharma, Using a database design appro...

Using a database design approach of your choice, produce a logical design for Pharma. 1) Your answer must consist of ONE the following: An entity-relationship (ER) diagra

Whst is logical schema, Whst is logical schema ? Logical schema is the ...

Whst is logical schema ? Logical schema is the entire database.

Inheritance, what is relationship inheritance and attribute inheritance

what is relationship inheritance and attribute inheritance

What are referential integrity constraints, What are referential integrity ...

What are referential integrity constraints? A value that appears in single relation for a given set of attributes also appears for a particular set of attributes in another rel

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