强实体和弱实体的区别

先决条件 – ER 模型
强实体：
强实体不依赖于模式中的任何其他实体。一个强大的实体总是有一个主键。强实体由单个矩形表示。两个强实体的关系由单个菱形表示。
各种强大的实体组合在一起时，会创建一个强大的实体集。

弱实体：
弱实体依赖于强实体来确保其存在。与强实体不同，弱实体没有任何主键。相反，它有一个部分鉴别器键。弱实体由双矩形表示。
一个强实体和一个弱实体之间的关系由双菱形表示。

强实体和弱实体的区别：

S.NO	Strong Entity	Weak Entity
1.	Strong entity always has primary key.	While weak entity has partial discriminator key.
2.	Strong entity is not dependent of any other entity.	Weak entity is depend on strong entity.
3.	Strong entity is represented by single rectangle.	Weak entity is represented by double rectangle.
4.	Two strong entity’s relationship is represented by single diamond.	While the relation between one strong and one weak entity is represented by double diamond.
5.	Strong entity have either total participation or not.	While weak entity always has total participation.