Implementing Relational Operators (cont)
So far, have considered file structures ...
- heap file ... tuples added to any page which has space
- sorted file ... tuples arranged in file in key order
- hash file ... tuples placed in pages using hash function
with relational algebra operations ...
- scanning (e.g.
select * from R)
- sorting (e.g.
select * from R order by x)
- projection (e.g.
select x,y from R)
- selection (e.g.
select * from R where Cond)
and now ...
- indexes ... search trees based on pages/keys
- signatures ... bit-strings which "summarize" tuples
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