Performing database joins
First Claim
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1. A method of performing a database join, comprising:
- receiving a query specifying a join of a first table and a second table;
determining a new predicate for the query based on a bit map, for a plurality of tuples of the join, between a first column of the first table, and a second column of the second table; and
modifying the query such that the query comprises the new predicate;
generating the bit map, wherein generating the bit map comprises;
determining a plurality of potential value pairs between the first column and the second column;
determining a plurality of actual value pairs in a plurality of tuples resulting from the join query; and
setting a bit in the bit map to 1 for each of the plurality of actual value pairs.
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Abstract
A method of performing a database join includes receiving a query. The query may specify a join of a first table and a second table. The method further includes determining a new predicate based on a mapping between a first column of the first table and a second column of the second table for a plurality of tuples of the join. Further, the method includes modifying the query such that the query comprises the new predicate.
15 Citations
11 Claims
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1. A method of performing a database join, comprising:
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receiving a query specifying a join of a first table and a second table; determining a new predicate for the query based on a bit map, for a plurality of tuples of the join, between a first column of the first table, and a second column of the second table; and modifying the query such that the query comprises the new predicate; generating the bit map, wherein generating the bit map comprises; determining a plurality of potential value pairs between the first column and the second column; determining a plurality of actual value pairs in a plurality of tuples resulting from the join query; and setting a bit in the bit map to 1 for each of the plurality of actual value pairs. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computer system for performing a database join, comprising:
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a memory; and a processor, configured to; receive a query specifying a join of a first table and a second table; generate a mapping that maps, for a plurality of tuples of the join, a first column of a first table to a second column of a second table; determine a new predicate for the query based on the mapping; and modify the query such that the query comprises the new predicate, wherein the mapping comprises a bit map, and wherein generating the mapping comprises; determining a plurality of potential value pairs between the first column and the second column; determining a plurality of actual value pairs in a plurality of tuples resulting from the join query; and setting a bit in the bit map to 1 for each of the plurality of actual value pairs. - View Dependent Claims (9)
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10. A non-transitory, computer-readable medium comprising machine-readable instructions executable by a processor to perform a database join, wherein the machine-readable instructions, when executed by the processor, cause the processor to:
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generate a bit map that maps a first column of a first table to a second column of a second table; receive a query specifying a join of a first table and a second table; determine a new predicate for the query based on the bit map; and modify the query such that the query comprises the new predicate, wherein generating the bit map comprises; determining a plurality of potential value pairs between the first column and the second column; determining a plurality of actual value pairs in a plurality of tuples resulting from the join query; and setting a bit in the bit map to 1 for each of the plurality of actual value pairs. - View Dependent Claims (11)
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Specification