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

Data redundancy, Data Redundancy -A lot of information is being repeated in...

Data Redundancy -A lot of information is being repeated in the relation. For instance, the information that MCS-014 is named SSAD is repetitive, address of Rahul is "D- 27, Main ro

Illustrate the class diagram for class room scheduling, Illustrate the clas...

Illustrate the class diagram for class room scheduling system If in any college, the number of classrooms are limited which have to be allocated to various classes and instruct

Relational algebra, Relational Algebra is a set of basic operations used to...

Relational Algebra is a set of basic operations used to influence the data in relational model. These operations allow the user to specify basic retrieval request. The result of re

Transactions t1 and t2 are in a deadlock, Evaluate: a.When transactions...

Evaluate: a.When transactions T1 and T2 are in a deadlock, one of the transactions will eventually implement to completion and let the other one continue implementation. b.

Explain entity integrity and referential integrity rules, Explain entity in...

Explain entity integrity and referential integrity rules within relational model. Show how these are realized in SQL? Entity Integrity Rule - No primary key value could be nu

01a_ImportCasting.xlsx, 01a_Broadway_LastFirst_yyyy-mm-dd Capstone Exercise...

01a_Broadway_LastFirst_yyyy-mm-dd Capstone Exercises You work as a production assistant in the office of the Green Man Theatre. One of your duties is to maintain the company datab

Explain categories of failures that occur in oracle database, Explain diffe...

Explain different categories of failures that occur in Oracle database? Categories of Failures - In Oracle database subsequent types of failures can occurred: Statement Failu

Find the employee name, Example -Find the employee name, salary, department...

Example -Find the employee name, salary, department number and average salary of his/her department, for those employees whose salary is more than the average salary of that depart

Writing a pl/sql program, Problem 1. Create a PL/SQL program to insert ...

Problem 1. Create a PL/SQL program to insert data into student table and display the details of the student having Reg.No 1010 Writing a PL/SQL program to Insert data

What are the strategies of implementation of the statecharts, What are the ...

What are the different strategies of implementation of the Statecharts?  There are two strategies for implementation of state charts: i)   Basic Implementation Strategy

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