Er diagram, and conversion into relational mode

1. Find the Entity (rectangle), attribute (ellipse), relationship (Diamond) relationship in the condition into 1:1,1:n,m:n, list er diagram

2.

Conversion method of -1:1 Contact

-Two entities are transformed into a relational schema, which is the original attribute

-The relationship can be merged with any entity, the attributes of the relationship, and the main code of the other entity to be added to the merged relational pattern

Transformation method of -1:n contact

-Two entities are transformed into a relational schema, which is the original attribute

-Relationship and N-side entity merging, relationship attributes, and the main code of another entity to be added to the merged relational pattern

Transformation method of--m:n contact

-Two entities are transformed into a relational schema, which is the original attribute

-The code of the relationship is the main code of two entities, and the attributes of the relationship, forming a new relational pattern

Er diagram, and conversion into relational mode