An entity is an object with a physical existence or it may be conceptual, so every organisation have some item or event of interest is called entity. It is described in a database a set of attribute. Every attribute is connected to one and only one entity.
For example, Student,Employee etc. are the entity.
Entity set are of two type---
a. Independent entity
b. Dependent entity
An independent entity is one that does not rely on another for identification.
A dependent entity is one that relies on another for identification.
What is entity set?
A group of similar object about which data are maintained in an organisation is called entity set, i.e., it is defined as a set of entities what are same type that share the same properties of attribute.
Entity set are of two type-------
a. Strong entity set
b. Weak entity set
a. Strong entity set:
An entity set that has a primary key is called a strong entity set. A strong entity is identify uniquely by consider primary key or composite primary key.
b.Week entity set:
An entity can be identified only by considering the primary key of owner entity called Weak entity.
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