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 a database, What is a Database? To know what database is, we ha...

What is a Database? To know what database is, we have to start from data, which is the basic building block of any DBMS. Data: Facts, figures, statistics etc. having no pa

HRM, is Chipo carrying his baby

is Chipo carrying his baby

State in detail about data flow diagram, What is a Data Flow Diagram?  ...

What is a Data Flow Diagram?  Data Flow Diagram: A data flow diagram is the graph that shows flow of data values from their sources in objects in the course of processes whic

Select statement-data manipulation language, SELECT Statement This stat...

SELECT Statement This statement is used for retrieving information from the databases. It can be coupled with many clauses. Let us talk about these clauses in more detail:

MS Access 2010 - Form Updates Table, Hi there, Have an issue with my Databa...

Hi there, Have an issue with my Database. I have: TblOrderDetails and FmOrderDetails TblCircuit and FmCircuit Whenever I add data into the Form, it will update the table as expect

What are the objectives of object design, What are the Objectives of object...

What are the Objectives of object design After going through this unit, you could be able to: explain steps of object design; discuss algorithms that reduce costs;

Determine advantages of merging an association into a class, What are the a...

What are the advantages and disadvantages of merging an association into a class?  Advantages: i)  Less number of tables ii) Faster performance due to the fewer tables

Which database object does not physically exist, Which database object does...

Which database object does not physically exist? A view database object does not physically exist.

Homework help, Draw an entity relationship diagram (ERD) for the following ...

Draw an entity relationship diagram (ERD) for the following situation: A company has a number of employees. Each employee is identified by an Employee_Id. The company wants to st

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