
ER Symbols
- ER model stands for an Entity-Relationship model.
- It is a high-level data model.
- The ER model defines the conceptual view of a database.
- It works around real-world entities and the associations among them.
| Symbols | Description |
| Entity | |
| Weak Entity | |
| Relationship | |
| Identifying Relationship | |
| Attribute | |
| Key Attribute | |
| Multivalued Attribute | |
| Composite Attribute | |
| Derived Attribute | |
| Total participation of E2 in R | |
| Cardinality Ratio 1:N 1E1 entity can be related to NE2 entity | |
| Structural Constraint (Min, Max) on participation of E in R | |
| Optional One | |
| Optional Many | |
| Mandatory One |