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

Relational schema for person, Example: RELATIONAL SCHEMA for PERSON: ...

Example: RELATIONAL SCHEMA for PERSON: PERSON (PERSON_ID: integer, NAME: string, AGE: integer, ADDRESS: String) RELATION INSTANCE In this instance, m = 3 and n = 4

Explain what is rdbms, Explain what is RDBMS ? RDBMS - RDBMS is a datab...

Explain what is RDBMS ? RDBMS - RDBMS is a database management system (DBMS) which stores data within the form of relations. Relational databases are powerful since they need f

Student database, tell me the functionality,advantages and disadvantages of...

tell me the functionality,advantages and disadvantages of student database

Create records in a table - data structures, In this exercise you will crea...

In this exercise you will create ten records, each containing the following fields: student name, class:  Freshman, Sophomore, Junior or Senior, Major:  Liberal Arts or General Sci

Construct a generalization-specialization hierarchy, Construct a generaliza...

Construct a generalization-specialization hierarchy for a motor-vehicle sales company. The company sells motorcycles that comprise an engine number and cost; cars that have a chass

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

What is key, What is key ? Key - A single attribute or a combination of...

What is key ? Key - A single attribute or a combination of two or more attributes of an entity set which is used to recognize one or more instances (rows) of the set (table) is

Explain the term- event, Event Occurrence of a process is called event...

Event Occurrence of a process is called event. In other words, the object can receive many input instructions. The changes which occur due to these instructions are known as e

design the logic using looping structure, 1. Design the logic, using a loo...

1. Design the logic, using a looping structure, for a program that outputs every even number from 1 through 25 along with its square and cube. 2. Mr. Sanchez owns 12 apartme

Need for distributed database systems, Need For Distributed Database System...

Need For Distributed Database Systems A distributed database is a set of database kept on multiple computers that appears to applications as a one database. As a result, an app

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