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

Consistency, what do you mean by consistency in rdbms?

what do you mean by consistency in rdbms?

State the steps of object design, State the Steps of Object Design ...

State the Steps of Object Design Object design is a very iterative process in which various classes, relationships among objects are added when you move from one level to

What three major types of actions includes databases, What three major type...

What three major types of actions includes databases? Briefly discuss these The three major types of actions including databases are: (i) Defining: It includes specifyin

Multilevel indexing scheme, Multilevel Indexing Scheme Consider the ind...

Multilevel Indexing Scheme Consider the indexing scheme where the address of the block is consider in the index for each record, for a little file, this index would be little a

The tools that are available for managing mysql server, Describe the tools ...

Describe the tools that are available for managing MySQL Server. Given below are the tools to manage MySQL server: mysqld - MySQL server daemon. This is used to begain t

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

Determine the minimal set of functional dependencies, Determine the minimal...

Determine the minimal set of functional dependencies for the following data. This table is part of the OHSU database of extracurricular activities and tracks the DMICE band's co

What is natural language interfaces, What is Natural Language Interfaces? ...

What is Natural Language Interfaces? Natural Language Interfaces - These interfaces accept requests written within English or a few other language and attempt to "understand" t

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