ER diagram

6. For the following Presidential ER diagram develop the relational schema using the pattern TableName(attribute-list).


http://jcsites.juniata.edu/faculty/rhodes/dbms/funcdep.html

• 2. Principles of mapping ER diagrams to relational schemas. Fill in the blanks with relation and attribute names.

a. If you have an entity E with attributes A, B and C in your ER diagram, with A as the primary key, what is its corresponding relation in relational schema? [3]
a.  ____E____ (    ____A, B, C_____________  )

b. If entity F has attributes  G, H and I with G as the primary key, but is related to entity E in a 1-many relationship, what is its corresponding relation? [4]
b.  ___F____ (    _____G, H, I, A________________  )

c. If entity L with attributes M, N and P with M as the primary key, and it is related to entity E in a many-many relationship called R, what is the corresponding relation that properly establishes the relationship?  [4]

                  ___R____ (    _______A,M__________________  )


jcsites.juniata.edu/faculty/rhodes/dbms/exams/mid2f13key.docx

• Limitations of E-R Designs

E-R modeling provides a set of guidelines, but does not result in a unique database schema.
Normalization theory provides a mechanism for analyzing and refining the schema produced by an E-R design, or any other design.
http://jcsites.juniata.edu/faculty/rhodes/dbms/funcdep.html