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

Calculate the record size r in bytes, An employee record has the following ...

An employee record has the following structure struct employee { int eno; char name[22]; float salary; char dept[10];}; (i) Calculate the record size R in bytes.

What is abstraction, What is abstraction? Abstraction in the object ori...

What is abstraction? Abstraction in the object orientation is a idea that provide opportunity to express necessary properties of object without providing much details of the im

Normalization, Introduction In large projects, we can have many different ...

Introduction In large projects, we can have many different companies working together. Generally, the project or contract is awarded to one company (Principal Contractor), which

Distributed query and transaction processing, Distributed query and transac...

Distributed query and transaction processing a.  Construct a query around any one of the functional divisions you made in 4a such that if executed in the distributed design of 4

Queries, Find the names of all Albums that have more than 30 tracks. Result...

Find the names of all Albums that have more than 30 tracks. Result: (name: varchar(255))

What is assertion, What is assertion? Mention the forms available. An a...

What is assertion? Mention the forms available. An assertion is a predicate expressing a condition that we wish the database always to satisfy. Domain integrity constraints.

What is dml, What is DML (Data Manipulation Language)? This language th...

What is DML (Data Manipulation Language)? This language that enable user to access or manipulate data as organised by appropriate data model. Procedural DML or Low level: DM

Er-diagram, courier company er-diagram

courier company er-diagram

How is the database organised in oracle, How is the database organised in O...

How is the database organised in Oracle? Database organized within Oracle in terms of table and table holds attributes and values. A database consists of one or more logical

Write a program within embedded sql to associative relation, Write a progra...

Write a program within embedded SQL to associative the total trip expenses of the salesman named ‘John' for the relations. EXEC SQL BEGIN DECLARE SECTION; long total_expenses;

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