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What are attributes and define its various types?

Database

ATTRIBUTES:- Attributes describe the properties of the entity of which they are associated. A particular instance of an attribute is a value, for e.g... Ram is one value of the attribute name. The domain of an attribute is the collection of all possible values an attribute can have. The domain of name is a character string.

We can classify attributes as following types:

      1. Simple attributes: A simple attribute is an attribute composed of a single component with an independent existence. Simple attribute cannot be further subdivided e.g. of simple attributes are sex, age, salary etc. simple attribute are sometimes called atomic attributes.
      2. Composite attributes: - An attributes composed of multiple component, each with an independent existences is called a composite attribute. Some attributes can be further divided for example the address attributes can be composed of components like street number, area, city, pin code and so on.
      3. Single valued attribute:- A single valued attributes is one that holds a single value for a single entity for e.g. the classroom entity has single value for the room number attribute& therefore the room-number attribute is referred to as being single- valued.
      4. Multi valued attribute:- That holds multiple values for a single entity for e.g. a student entity can have multiple values for the hobby attribute- reading, singing, dancing etc
      5. Derived attribute-:: is one that represents a value that is derivable from the value of a related attribute or set of attributes for e.g. age attribute can derived from the date of birth attribute.

 

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