Definition
Entity: An object or thing that exists in the real world is called an entity. A customer, a car, a pen, etc.
The database contains entities that must be recognized from the group in order to be placed there. A collection of pens from the same business, for instance, are just objects as they cannot be identified; but, pens with distinct colors—such as red, green, blue, black, etc.—become unique and are referred to as entities.
Entity Type: An entity type is a grouping of entities that share common characteristics.
A corporate company's database, for instance, contains entity types like departments, employees, and so forth. Each entity type in DBMS has a collection of characteristics that describe the entity.
Attributes including name, age, address, phone number, and pay can be found in the Employee entity type.
The Department entity type might have attributes including name, number, and departmental location.
Kinds of Entity Types :
1. Strong Entity Type
2. weak Entity Type
1. Strong Entity
A strong Entity is independent and has its own existence. The entity relationship diagram uses a single rectangle to represent a strong entity type.
2. Weak Entity
It is a creature that depends on a powerful entity to sustain it rather than having an existence of its own. Double rectangles are used in the Entity Relationship Diagram to represent the weak entity type.
