| �Boolean� refers to George Boole, an 18th century British mathematician who developed much of the logic that underlies computer science | |
| �Operators� are mathematical recipes, e.g., in 2+2=4, �+� is the addition operator. | |
| �Boolean operators� are recipes for logical combinations |
| AND � both concept keywords connected by this operator must be present on the Web, database, catalog, etc. page for a result (�hit�) to be returned | ||
| Facebook AND privacy | ||
| AND is the default for most search engines | ||
| OR � either keyword connected by this operator must be present on the Web, database, catalog, etc. page for a result (�hit�) to be returned | ||
| Facebook OR MySpace | ||
| Copyright OR Copywrong | ||
| AND vs. OR:� Copyright Law | |
| AND:� 3,450,000 hits on AltaVista | |
| AND: 6,360,000 hits on Google | |
| AND:� 3,450,000 on Yahoo | |
| OR:� 266,000,000 hits on AltaVista | |
| OR:� 269,000,000 on Google | |
| OR:� 267,000,000 on Yahoo |
| The solution is to search on the phrase Copyright Law,which is done by placing it in double quotes: | |
| �Copyright Law� | |
| This is now almost universal among search engines. |
| Copyright Law | |
| default = AND: 3,450,000 hits on AltaVista | |
| default = AND: 6,360,000 hits on Google | |
| default = AND: 3,450,000 on Yahoo | |
| �Copyright Law� | |
| 1,670,000 hits on AltaVista | |
| 3,480,000 hits on Google | |
| 1,670,000 on Yahoo |
| NOT � second keyword connected by this operator must NOT be present on the Web, database, catalog, etc. page for a result (�hit�) to be returned | ||
| Facebook NOT instant messaging | ||
| Copyright NOT music | ||
| BE CAREFUL | ||
| NOT | ||
| can weed out good resources | ||
| NEAR � second keyword connected by this operator must be adjacent to the first on the Web, database, catalog, etc. page for a result (�hit�) to be returned | ||
| Facebook NEAR privacy | ||
| �Copyright law� NEAR graphics | ||
| �adjacent� usually means within 10 words | ||
| There are two other search tools that are not logical operators, but they are most often combined with Boolean terms to refine searches � �wildcard� and �nesting.� |
| �wildcard� � using a special symbol, usually an asterisk (*), to search for part of a word | ||
| �instant messages� might miss statements such as �X and Y announced today that instant messaging is the best form of communication.�� Try this instead: | ||
| instant messag*� | ||
| �nesting� � using parentheses to combine various operators and lessen ambiguity | |||
| �Copyright law helps with using graphics on Web sites � � long, full of assumptions� | |||
| assumes all words present | |||
| assumes graphics, not graphic images | |||
| assumes Web sites, not Web pages or Internet sites | |||
| �nesting� � using parentheses to combine various operators and lessen ambiguity | ||
| �Copyright law helps with using graphics on Web sites � �long, full of assumptions� | ||
| An alternative: | ||
| �Copyright law� AND graphic* AND (�Web sites� or� �Web pages� OR �Internet sites�) | ||
| An alternative: | ||
| �Copyright law� AND graphic* AND (�Web sites� or� �Web pages� OR �Internet site�) | ||
| Another possibility: | ||
| �Copyright law� AND (graphic* or graphic image*) AND ((Internet� or Web) NEAR (page* or site*)) | ||
| But use caution � nesting is very powerful but an easy place to make mistakes | ||
| The classic operators: | |
| AND | |
| OR | |
| NOT (AND NOT) | |
| NEAR | |
| And the additions: | |
| �phrase in double quotes� | |
| wildcard | |
| nesting |