Relational algebra and functional programming
- Relational algebra operates on relations.
- An operation takes 1-2 relations as input, and yields another
relation as output.
- In practice, query processing avoids explicitly forming new
relations (tables) whenever possible.
- Operate on streams of tuples instead, when possible.
- This also reflects the way that query results are used: one row
at a time, through a cursor or iterator, (which may be
stopped before data is fully consumed).