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TALON MODULE 4: Performing Effective Searches in Electronic Databases
Nested Boolean Logic

Nested Boolean logic, also called nesting, allows you to create a complex search by combining multiple logical operators in the same search.

By using parentheses you can separate and "nest" the parts of the search statement having these different connecting operators.

animation of nested Boolean using overlapping circles

For example, advertising and (lawyers or attorneys). The part of the search enclosed in parentheses, lawyers or attorneys, will be performed first, followed by the AND operation. Thus, this search will retrieve items on advertising and lawyers as well as works on advertising and attorneys.

The light green area, where the purple circles overlap the yellow circle, represents the results of the search advertising and (lawyers or attorneys).

Important: If you do not use parentheses, the operators will be performed from left to right and your results may not be what you intended.


Concept & Design by Laurie Preston
Content Authored by
Laurie Preston & Jack Bales
Reviewed/Updated
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