Notations | Representation | Description |
---|---|---|
Rectangle | It represents the Entity. | |
Ellipse | It represents the Attribute. | |
Diamond | It represents the Relationship. | |
Line | It represents the link between attribute and entity set to relationship set. | |
Double Rectangle | It represents the weak entity. | |
Composite Attribute | It represents composite attribute which can be divided into subparts. For eg. Name can be divided into First Name and Last Name | |
Multi valued Attribute | It represents multi valued attribute which can have many values for a particular entity. For eg. Mobile Number. | |
Derived Attribute | It represents the derived attribute which can be derived from the value of related attribute. | |
Key Attribute | It represents key attribute of an entity which have a unique value in a table. For eg. Employee → EmpId (Employee Id is Unique). |