Relational Algebra
Relational algebra (RA) can be viewed as ...
- mathematical system for manipulating relations, or
- data manipulation language (DML) for the relational model
Core relational algebra operations:
- selection: choosing a subset of rows
- projection: choosing a subset of columns
- product, join: combining relations
- union, intersection, difference: combining relations
- rename: change names of relations/attributes
Common extensions include:
- sorting (
order by), - partition (
group by), aggregation
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