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

Synonyms and indexes, Synonyms and Indexes Some of the essential proper...

Synonyms and Indexes Some of the essential properties of indexes are: An Index is a schema Object Indexes can be formed explicitly or automatically Indexes are m

Foreign keys , Foreign Keys and NULL Let us take the relation:         ...

Foreign Keys and NULL Let us take the relation:                 DEPT DEPT ID DNAME BUDGET D1 M

Data mining, 1.Why we need data mining? Give an example to illustrate your ...

1.Why we need data mining? Give an example to illustrate your answer. 2. Why data mining is considered as "misleading name"? 3. Distinguish the difference between database an

What are the objectives of object design, What are the Objectives of object...

What are the Objectives of object design After going through this unit, you could be able to: explain steps of object design; discuss algorithms that reduce costs;

Define the term- state, State The position of object at any moment is ...

State The position of object at any moment is called state. An object can have many states depend upon time. After receiving some input instructions, the object can change its

Why as clause is used in sql, Why 'AS' clause is used in SQL ? 'As' cla...

Why 'AS' clause is used in SQL ? 'As' clause is used for Rename operation. ‘AS' clause is used in SQL for rename operation. (e.g., SELECT ENO AS EMPLOYEE_NO FROM EMP)

Need customer management program, Project Description: This is a Custome...

Project Description: This is a Customer Management project. Customer data is presented in a text file. The program can load this text data into its database columns. The data ma

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