Explain weak and strong entity type, Database Management System

Assignment Help:

Explain weak and strong entity type ?

Weak and Strong entity type: An entity set which does not have a primary key is referred to as a weak entity set. The existence of a weak entity set depends on the existence of a strong entity set; it must associate to the strong set via a on-to-many relationship set. A discriminator of a weak entity set is the set of attributes that distinguishes between all the entities of a weak entity set. The primary key of a weak entity set is formed by the primary key of the strong entity set on that the weak entity set is existence depends, plus the weak entity set's discriminator.


Related Discussions:- Explain weak and strong entity type

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

Define entity integrity and referential integrity, Define entity integrity ...

Define entity integrity and referential integrity.  How does SQL allow specification of  these? Ans: Entity Integrity Rule- If the attribute A of relation R is a prime attribut

What is the use of with clause in sql, What is the use of with clause in SQ...

What is the use of with clause in SQL? The with clause gives a way of defining a temporary view whose explanation is available only to the query in which the with clause occurs

Define an operator that a relational algebra does not have, Define an opera...

Define an operator that a Relational Algebra does not have Ans: Relational Algebra does not have Aggregation operators.

What is a value, What is a value? A data value is used for identity. Th...

What is a value? A data value is used for identity. This form of identity is used in relational systems.eg: The primary key value of a tuple recognize the tuple.

Improved performance, Improved performance: As the data is located near the...

Improved performance: As the data is located near the site of its demand, and given the inherent parallelism because of multiple copies, speed of database access may be good for di

What is data independence, What is data independence? Data Independenc...

What is data independence? Data Independence: Techniques which permit data to be changed without affecting the applications in which procedure it. There are two types of data

Relationship sets, A relationship set is a set of relationships of the simi...

A relationship set is a set of relationships of the similar type. For example, let consider the relationship among two entities sets course and student. Collection of all the in

State the functional approach of object oriented methods, State the functio...

State the functional approach of object oriented methods Moving from a functional approach to an object oriented one needs a translation of functional model elements into objec

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