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Course:
Research Note Topic:
Research Note Description:
The design and implementation of My Students Database is based upon Codd's relational algebra. The eight operators for Codd’s relational algebra are:
1. Restriction:
Returns a table containing all records from a specified table that satisfy a specific condition.
2. Projection:
Returns a table containing all (sub) records that remain in a specified table after specified fields have been removed.
3. Product:
Returns a table containing all possible records that are a combination of two records, one from each of two specified tables.
4. Union:
Returns a table containing all records that appear in either or both of two specified tables.
5. Intersection:
Returns a table containing all records that appear in both of two specified tables.
6. Difference:
Returns a table containing all records that appear in the first but not the second of two specified tables.
7. Join:
Returns a table containing all possible records that are a combination of two records one from each of two specified tables, such that the two records contributing to any given combination have a common value for the common fields of the two tables (and that common value appears just once, not twice in the resulting record).
8. Division:
Takes two single-field tables and one double-field table and returns a table containing all records from one single-field table that appear in the double-field table matched with all records in the other single-field table.
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Prof. Ashay Dharwadker