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

Frequecy count, how to calculate frequency count of algorithm

how to calculate frequency count of algorithm

State the object design for processing, State the Object Design for Process...

State the Object Design for Processing  The object design phase comes after analysis and system design phase. The object design phase includes implementation details like as i

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

Primary key, The primary key is selected from the

The primary key is selected from the

Gui interfaces, Draw the database using the ER approach and then make the t...

Draw the database using the ER approach and then make the tables accordingly. Populate the tables so that every table have at least 10 tuples. Then using Java and SQL, execute the

DW Job Scheduling, Define a job scheduling strategy that will meet business...

Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pictori

Two types of blocks in the fixed -length representation, What are the two t...

What are the two types of blocks in the fixed -length representation? Define them. Anchor block: Have the first record of a chain. Overflow block: Have the records other tha

Define the term- actors and data stores, Define the term- Actors and Data...

Define the term- Actors and Data Stores Actors: An actor is the active object which drives data flow graph by producing or consuming values. Actors are attached to inputs a

Record based logical models, Record based Logical Models: Use records as th...

Record based Logical Models: Use records as the key data representation components Examples: Relational Model: It shows data as well as relationship between data in the form

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