Varieties of Selection
Selection: select * from R where C
- filters a subset of tuples from one relation
R
- based on a condition
C on the attribute values
We consider three distinct styles of selection:
- 1-d (one dimensional) (condition uses only 1 attribute)
- n-d (multi-dimensional) (condition uses >1 attribute)
- similarity (approximate matching, with ranking)
Each style has several possible file-structures/techniques.
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