Attempting to reconnect
Hang in there while we get back on track
Extended Entity Relationship Mapping
Stephen M. Reaves
::
2023-06-15
Notes about Lesson 5 of CS-6400
Summary
Mapping
You can map from EER to Relational models
G cluster_user User User User Email Email User--Email Password Password User--Password C C User--C D D C--D E E C--E UR Email Password D E Multi-Instance Type
Multi-instance types become a seperate table that has a composite key composed
of the original key plus the mulit-instance type. The original key is also now
a foreign key on the new table.
G cluster_user User cluster_user_f User-F User User Email Email User--Email Password Password User--Password F F User--F UR Email Password URF Email F Relations
G cluster_ET1 ET1 cluster_ET2 ET2 ET1 ET1 R R ET1--R A A ET1--A ET2 ET2 B B ET2--B R--ET2 UR A URF B A Many to Many relations require a join table.
G cluster_ET1 ET1 cluster_et2 ET2 cluster_r R ET1 ET1 R R ET1--R M A A ET1--A ET2 ET2 B B ET2--B R--ET2 N e1 A e3 B r A B
