Database Reference
In-Depth Information
In this section we are going learn how to mapping of relationships. Before mapping go
through these steps
 Identify the entities
 Add attributes to entities, identifying primary keys:
 What relationship is there
3.8.1 Rule: mapping M:M relationships
For each M:M relationship, form a new table ( relation) with the primary keys of both of
the two entities (owner entities) that are being related in the M:M relationship. The key of
this newly created table will be the concatenated keys of the owner entities. Include any
attributes that the M:M relationship may have in this new table.
Example 6:
For example, refer to following ER diagram. The student and course tables have
the following data:
x
= students, y = courses, relationship = admission
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