Entity-Relationship Diagram
An entity is an object or thought about which you want to store information in database.
Entity-Relational Model considers the real world consisting of a set of basic objects and that objects is called entity. And this shows the logical structure of database.
Entity-Relationship Diagram is a graphical structure of a database. Showing this graphical structure we use some special symbol that’s given.
| Rectangle |  |
Represents entity sets |
|---|---|---|
| Eclipses |  |
Represents attributes |
| Diamonds |  |
Represents relationship sets |
| Lines | Links attributes to entity sets and entity sets to relationship | |
| Double rectangle |  |
Represents weak entity sets |
| Double eclipses |  |
Represents Multivalued attributes |
| Dashed eclipses |  |
Represents derived attributes |
| Double lines | Represents total participation of an entity in a relationship set |
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