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

Define tables students and teachers as sub tables of people, Write a query ...

Write a query to define tables students and teachers as sub tables of people? Create table students of student under people Create table teachers of teacher under people

What is view in sql, What is view in SQL? How is it defined? Any relati...

What is view in SQL? How is it defined? Any relation that is not part of the logical model, but is made visible to a user as a virtual relation is known as a view. We descri

Differentiate between logical database design and physical, Differentiate b...

Differentiate between logical database design and physical database design. Show how this separation leads to data independence? Basis Logical Databas

Primary and foreign key, Primary Key The primary key is the candidate k...

Primary Key The primary key is the candidate key that is selected by the database designer as the principal denotes of identifying entities within an entity set. The left candi

What are the two types of serializability, What are the two types of serial...

What are the two types of serializability? The two types of serializability is a)      Conflict serializability b)      View serializability

Define database management system, Normal 0 false false fal...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Write a short note on qbe, Write a short note on QBE? Stands for "Quer...

Write a short note on QBE? Stands for "Query By Example." QBE is a feature involved along with various database applications which gives user-friendly techniques of running da

Design and building a distributed information system, The scenario You ...

The scenario You have been approached to design and implement a prototype of a distributed information system for a national car part retail outlet chain. The company comprises

What are the kinds of strings, What are the kinds of Strings?  -A binar...

What are the kinds of Strings?  -A binary string in MySQL is one that MySQL treats as case sensitive in comparisons. -A non binary string in MySQL is one that MySQL does'nt

Determine the derived attribute to avoid re-computation, Determine the Deri...

Determine the Derived attribute to avoid re-computation Each class box consists of an ordered list of attributes and operations, each represented as a next string. We can find

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