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

Employee elation with information, Consider a database application that dea...

Consider a database application that deals with an Employee relation with information such as SIN, name, data of birth (DOB), and DID (the ID of the department at which the employe

Explain the outer join, Define Outer join Outer join - If there are any...

Define Outer join Outer join - If there are any type of values in the one table that do not have corresponding value(s) in the other, in an equi-join which will not be selected

Dbms, Retrieve the S&S In-Chapter Database (in Microsoft Access format) fro...

Retrieve the S&S In-Chapter Database (in Microsoft Access format) from the text's Web site (or create the tables in Table 4-5 in a relational DBMS product). Write queries to answer

What are composite attributes, What are composite attributes? Composite...

What are composite attributes? Composite attributes can be separated in to sub parts.

Architecture, With the help of a suitable diagram gives module wise explana...

With the help of a suitable diagram gives module wise explanation of system architecture of DBMS.on..

Define the concept of object diagram, Define the concept of Object Diagram ...

Define the concept of Object Diagram An object diagram shows a set of the objects and their relationships with each other at a point of time. In a static view, object diagram

What is an operand, What is an Operand? The data on which the operation...

What is an Operand? The data on which the operation is to be performed is known as an Operand

Define the concept of aggregation, Define the concept of aggregation.  Give...

Define the concept of aggregation.  Give two examples where this concept is useful. Ans: Aggregation transforms a relationship among the objects into a higher-level object. A

The sap profile parameter, While sorting, if the main storage available is ...

While sorting, if the main storage available is not enough, the system writes data to an external help file.  The SAP profile parameter, which determines DIR_SORTTMP

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