Weak entity, Database Management System

Assignment Help:

Entity types that do not have any key attribute, and therefore cannot be identified independently, are known as weak entity types. A weak entity can be recognized uniquely only by considering some of its attributes in conjunction with the primary key attributes of another entity, which is known as the identifying owner entity.

Usually a partial key is attached to a weak entity type that is used for unique identification of weak entities associated to a particular owner entity type. The following restrictions must hold:

  • The weak entity set and the owner entity set must participate in one to many relationship set. This relationship set is known as the identifying relationship set of the weak entity set.
  • The weak entity set necessary to have total participation in the recognized relationship.

 


Related Discussions:- Weak entity

What is the use of with clause in sql, What is the use of with clause in SQ...

What is the use of with clause in SQL? The with clause gives a way of defining a temporary view whose explanation is available only to the query in which the with clause occurs

Differentiate oo development from structured development., Differentiate OO...

Differentiate OO development from structured development. Structured approach of problem solving is based upon the idea of decomposition of system into subsystem. In this appro

What is entity in dbms, What is entity in DBMS? Entity: A DBMS entity i...

What is entity in DBMS? Entity: A DBMS entity is either a thing in the modelled world or a drawing element in an ERD.

Thid, describe objectivde of file organisation

describe objectivde of file organisation

converting eerd, Create centralized relational database using Top down met...

Create centralized relational database using Top down method- Construction of Logical Model: Translation EERD into Relational Schema: Use the 8 steps algorithm of converting EERD

Define deadlock avoidance, Define Deadlock avoidance These protocols a...

Define Deadlock avoidance These protocols as well ensure that the system will never enter a deadlock state although the way it is done is different from deadlock prevention. I

Process of implementing system design in dynamic models, Process of impleme...

Process of implementing system design in dynamic models There are three essential approaches to implementing system design in dynamic models. These approaches are as below:

Develop a fragment of a hypothetical system, The objectives of this assignm...

The objectives of this assignment are:  - to develop skills in the design of database driven applications  - to develop skills in applying SQL to implement the relational and

desirable properties of decomposition, Desirable Properties Of Decompositi...

Desirable Properties Of Decomposition Decomposition is a process of dividing a relation into its projections that will not be disjoint. Please remind the Relational projection

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

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