Database - ER Model and Business Rules - Discussion
Discussion Forum : ER Model and Business Rules - General Questions (Q.No. 11)
11.
A subtype discriminator is which of the following?
Discussion:
1 comments Page 1 of 1.
SUJITH-SpT said:
1 decade ago
A Subtype Discriminator is an attribute of the Supertype that is used to "code" or denote which Subtype an entity is.
Example: We might code EMPLOYEE supertypes as either "H" or "S" for HOURLY or SALARIED employee subtypes.
This attribute may enhance system performance during program coding of maintenance programs for the database tables during the physical design phase of a project.
While your text discusses various ways to use Subtype Discriminators for Disjoint or Overlapping subtypes, coding of the attribute in the Supertype will handle all possibilities.
Example: We might code EMPLOYEE supertypes as either "H" or "S" for HOURLY or SALARIED employee subtypes.
This attribute may enhance system performance during program coding of maintenance programs for the database tables during the physical design phase of a project.
While your text discusses various ways to use Subtype Discriminators for Disjoint or Overlapping subtypes, coding of the attribute in the Supertype will handle all possibilities.
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