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

Design and building a distributed information system, prototype of a distri...

prototype of a distributed information system for a national car part retail outlet chain.

Relationship, what is the relationship between receipt and owner entities i...

what is the relationship between receipt and owner entities in computer sales and service company

Create a e-r diagram or uml class diagram, We require an advanced system fo...

We require an advanced system for a Sports Centre, you are concerned only with representing the data discussed below about bookings and members. (The complete system may contain ot

What are the various symbols used to draw an e-r diagram, What are the vari...

What are the various symbols used to draw an E-R diagram? Explain with the help of an example how weak entity sets are represented in an E-R diagram. Various symbols used to d

What are the types of indices, Normal 0 false false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What is an index, What is an Index? An index is a small table having on...

What is an Index? An index is a small table having only two columns. The first column has a copy of the primary or candidate key of a table and the second column having a set o

What is relational calculus, What is Relational calculus? Relational c...

What is Relational calculus? Relational calculus is a Non- Procedural language.

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