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What are the types of entities in database
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Types of entities :

There are two types of entities.

1] Strong entity - An entity is a things or object in real world that is distinguishable from all other object.

  • For example, every employee in the organization in an entity.

  • Every entity is separated by some set of properties.

  • Strong entity may have more or one properties.

  • For example: employee entity can be represented by properties like employee-id, name, email, etc.

  • Strong entity is represented by rectangle as

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  • Attribute which is used to identify entity uniquely is primary and denoted as

Weak entity - entity type that don't have key attributes of DWN are called weak entity.

entities belonging to weak type are identified by being related to specified strong entities.

  • Those strong entities are called as identifying entities and relationship with weak entity is called weak relationship.

  • It is represented as

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Example

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Here the name attribute is partial key.

  • Using attribute name relationship and age it is not possible to uniquely identify dependent.
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