2.      We listed six (6) basic steps in mapping ERDs to RDBMS tables. List them and explain how each one works.

 

Step 1: Map Regular Entities

 

 

If there are no composite/complex attributes, mapping of entities is straightforward

 

 

 

Step 2: Map Weak Entities

 

Since a weak entity can not exist without the referenced entity, add the appropriate foreign

 

key(s)

 

Step 3: Map Binary Relationships

 

 

 

Map Binary 1:1, 1:M, and M:1 relationships

Remember that in M:1 and 1:M relationships, the foreign key goes on the side of the MANY

 

Step 4: Map Associative Entities (M:M)

 

 

 

Create the necessary table.

The primary key is a composite of each of the primary keys from the associated tables and any other keys needed to construct a unique identifier

 

Step 5: Map Unary Relations

 

If a 1:M relationship, no additional tables required.

If a M:M relationship, the associative table again becomes a table

 

 

Step 6: Map Ternary (and n-ary) relationships

 

Any combination other than a 1:1:1 results in an associative entity