Step 1. Mapping of Regular Entity Types
For each regular entity type E in the ER schema, create a relation R that includes all the simple attributes of E. Choose one of the key attributes of E as the primary key for R.
Step 2. Mapping of Weak Entity Types
Create a relation R and include all simple attributes. Combine the primary key of the owner and the partial key of the weak entity as the key
Step 3. Mapping of Binary 1:1 Relationship Types
For relations S and T
- Foreign key approach, set the key in S as the foreign key in T
- Merged relation approach
- Cross-reference or relationship relation approach
Step 4. Mapping of Binary 1:N Relationship Types
For 1:N relation of T and S, S is the N-side. Include as foreign key in S the primary key of T
Step 5. Mapping of Binary M:N Relationship Types
For M:N relation of T and S, create a new relation R. Include as foreign key in R the primary keys of T and S. The primary key is the combination of the foreign key attributes.
Step 6. Mapping of Multivalued Attributes
For each multivalued attribute A, create a new relation R.
Step 7. Mapping of N-ary Relationship Types
For each n-ary relationship type R, where n > 2, create a new relation R.