What is E-R diagram[DBMS-4]

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E-R diagram

-E-R diagram is the entity relationship diagram.
-E-R diagram can express the logical structure of the database graphically.
-E-R diagram can consist of the following major components.


-The entity sets are represented by the rectangular.










-The attribute are represented by the ellipse.











-The relationship are represented by the diamond and rhombus.











-Line is used to link attribute to entity sets and entity sets to relationship sets.




-double ellipse is represented to composite attributes.









-Dotted ellipse is represented to dotted derived attributes.







It is represented to composite attributes.










-Key attributes.






-Double rectangle represented to work of entities.













-Double line indicate to the particularization of an entity set in the relationship sets.






-One to one


-One to many


-Many to one



-Many to may

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