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 DB2  |  Question 57 of 196    Print  
Compare a subselect to a join. Any subselect can be rewritten as a join, but not vice versa. Joins are usually more efficient as join rows can be returned immediately, subselects require a temporary work area for inner selects results while processing the outer select.

  
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Denormalizing DB2 tables reduces the need for processing intensive relational joins and reduces the number of foreign keys.  
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