Database Reference
In-Depth Information
3.8.3 Rule: Mapping 1:M relationships with partial participation
For binary 1:M relationships, if the M-side has partial participation, the 1:M relationship is
handled just like a binary M:M relationship. A separate table is created for the relationship.
The key of the newly created table consists of a concatenation of the keys of the related
entities. Include any attributes that were on the relationship, on this new table.
3.8.3 Rule: Mapping 1:1 relationships
For binary 1:1 relationships, include the primary key of Entity X into Entity Y as the for-
eign key.
Example:
In the following ERD there is One to one relationship between employee and
house
To map this relation ship key is added to any one the table like EmployeeID is added to
house relation
