Attributes and Types of Attributes in DBMS

Attributes are the properties which describe an entity.

Example

The attributes of student entity are as follows −

• Roll number

• Name

• Branch

• Age

Types of attributes

The different types of attributes are as follows −

Composite attribute

It can be divided into smaller sub parts, each sub part can form an independent attribute.

For example −

                                             Name
                                 FirstName MiddelName LastName

Simple or Atomic attribute

Attributes that cannot be further subdivided are called atomic attributes.

For example −

                        Phone number
                        PIN code

Single valued Attribute

Attributes having a single value for a particular item is called a single valued attribute.

For example: Room Number

Multi-valued Attribute

Attribute having a set of values for a single entity is called a multi-valued attribute.

For example −

               e-mail
               Tel.No
               Hobbies

Derived Attributes or stored Attributes

When one attribute value is derived from the other is called a derived attribute.

For example: Age can be derived from date of birth, where,

• Age is the derived attribute.

• DOB is the stored attribute.

Complex Attribute

Nesting of composite and multi-valued attributes forms a complex attribute.

For example

If a person has more than one house and each house has more than one phone. Then, that attribute phone is represented as a complex attribute.