Entity identifier key attributes, Database Management System

Assignment Help:

An entity type usually has an attribute whose values are distinct for every individual entity in the collection. Such an attribute is known as a key attribute and its values can be used to recognize each entity uniquely.

Strong entity set: The entity types having a key attribute are known as strong entity types or regular entity types.

  • EXAMPLE: The Student entity has a key attribute RollNo which uniquely recognized it, hence is a strong entity.

Attributes

Let us first answer the question:

What is an attribute?

An attribute is a property used to define the specific feature of the entity. So to define an entity entirely, a set of attributes is used.

For example, a student entity may be defined by the student's name, address, age, course, etc.

An entity will have a value for every of its attributes. For example for a specific student the following values can be assigned:

RollNo: 1234

Name: Supriya

Age: 18

Address: B-4, Mayapuri, Delhi. Course: B.Sc. (H)


Related Discussions:- Entity identifier key attributes

Write a query to find name from the relational algebra, Consider the relati...

Consider the relations City (city_name, state) Hotel (name, address) City_hotel (hotel_name, city_name, owner) Answer the following queries in relational algebra (i) Find

What is the use of group by clause, What is the use of group by clause?  ...

What is the use of group by clause?  Group  by  clause  is  used to apply  aggregate  functions  to a  set  of  tuples. The attributes given in the group by clause are used to

What is relational model feature, What is relational model feature? A r...

What is relational model feature? A relational model feature is much more data independence than some other database models.

Need senior oracle database administrator, Project Description: Oracle C...

Project Description: Oracle Certified Professional with 20 years of practice, Oracle version 6.0.34, 7.3, 8.0, 8i, 9i, 10G, 11G, 12C. Crossplatform migration, Informix, MSSql

What are object interaction diagrams, What are object interaction diagrams?...

What are object interaction diagrams? Object interaction diagrams are the diagrams that used to describe order in which messages are communicated in execution of an operation,

Order by clause-data manipulation language, Order by clause By usin...

Order by clause By using this rows can be sorted It is used in the last portion of select statement By default it gets ascending order DESC: is used

What is known as fudge factor, What is known as fudge factor? The numbe...

What is known as fudge factor? The number of partitions is enhanced by a small value called the fudge factor, which is usually 20 percent of the number of hash partitions compu

Hoework, Farmer Bob, Farmer Jane and Farmer Jose run a cow farming co-op. ...

Farmer Bob, Farmer Jane and Farmer Jose run a cow farming co-op. For every cow they keep the cow’s name, age (or date of birth), breed and numbered plastic ear tag. The each of t

Equi-join, explain equi-join using illustration

explain equi-join using illustration

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