Database Reference
In-Depth Information
For multi-valued attributes, make a separate table for the multi-valued attribute. Keep a
row for each value of the multivalued attribute, with the key from the original table. The
key of the new table will be the combination of the multivalued attribute and the key of the
owner entity. Eliminate the multi-valued attribute from the original table.
Example 5:
In the following figure school is multi value attribute where that a student may
have more than one school.
Now suppose that the above example had name as a key. It would be mapped
into two relations: a relation with the multi-valued attribute, and a resulting relation
with the multi-valued attribute excised.
