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

3-schema architecture, Gyan Gurukul is a software company that provides sof...

Gyan Gurukul is a software company that provides software related solution. Ashutosh Dubey who is the director of Gyan Gurukul want a three-level schema architecture for the Gyan G

Sparse and dense indexes, Sparse and Dense Indexes These indexes in pri...

Sparse and Dense Indexes These indexes in principle are the similar as that of indexes used at the back of the book. The key facts of the indexes are: They are arranged

What is the use of unique function, What is the use of unique function? ...

What is the use of unique function? UNIQUE function: If UNIQUE is specified then only unique values are used to computed the mean.

When it is better to use files than a dbms, When It is better to use files ...

When It is better to use files than a DBMS? It is better to use files than a DBMS when Multiple users wish to access the data.

Create student db and perform delete operation, Create Student DB and perfo...

Create Student DB and perform delete operation? STUDENT (name, student#, class, major) COURSE (course name, course#, credit hours, department) SECTION (section identifier, co

Explain the concept of data mining, Question 1 Explain the concept of Fore...

Question 1 Explain the concept of Foreign Key. How a foreign key differs from a Primary Key? Can the Foreign Key accept nulls? Question 2 With a necessary example explain (i)

What are the components of storage manager, What are the components of stor...

What are the components of storage manager? The storage manager components include a) Authorization and integrity manager b) Transaction manager c) Buffer manager d

Entity relationship, how to write tables and drow E-R diagrams for hosiptal...

how to write tables and drow E-R diagrams for hosiptal management system and how to normalize and cardinalities?

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