Our text covers only some of the possible operations.
(For a more complete list, see Elmasri & Navathe, page 518.)
Also, it makes sense to combine the implementation of various sets of
operations in order to reduce the size of intermediate relations:
- Combine projects and selects with a Cartesian product or natural join.
- The idea is to do the selection and/or projection while computing the
join.
- This saves computing a large intermediate relation that is going to be
subsequently reduced by the select or project anyway.
