George Boole was a 19th century English mathematician who developed a method of symbolic logic. Boolean searching on the computer is based on this symbolic logic. Most online databases and search engines support Boolean searches. Boolean search techniques can be used to carry out effective searches, cutting out many unrelated documents.
When Using Boolean Logic On The Computer, There Are 3 Operators:
In order to see how these Boolean Operators work let’s go to the “Boolean Machine”
So in other words: When you use the Boolean Operator AND or +, both conditions must be met— all other results are thrown out.
When you use the Boolean Operator OR, you are widening your search and telling the computer that you want results from any of the search terms.
When you use the Boolean Operator NOT or –, you are narrowing your search by excluding records containing certain terms.
When you are searching for “Mars” the Roman God of War and you DON’T want results for the planet “Mars” popping up. NOT Mars AND “Roman god of war” NOT planet
Or you are searching for “Paris” the capital of France and you DON’T want results for “Paris Hilton” popping up. NOT Paris AND France NOT “Paris Hilton”
The 2 Previous Slides Contained Examples Of Using Quotes ☼This tells the search engine to give you pages where the terms that you surrounded with quotes appear in exactly the order you specified. ☼This will exclude any results where they do not appear in that order. Mars AND “Roman god of war”
At Some Other Search Strategies Let’s Look * Truncation & ? Wildcards #
Truncation Use truncation and wildcards to retrieve variations of search terms. The truncation symbol (*) serves as a substitute for any string of zero or more characters. For example, the search golf* retrieves articles containing the words golf, golfing and golfer(s), as well as golfball(s).
Wildcards The wildcard symbol (?) serves as a substitute for one character or none. For example, the search m?cdonald retrieves both mcdonald and macdonald AND The search dra???t retrieves both draft and draught.
Different Wildcard Symbols May Be Used Depending On The Search Engine That You Are Using! * ? # !
The Same Thing Holds True For Other Aspects Of Boolean Searching— Because rules may vary depending on the program you are using; you need to check out the “Help” section of all programs to determine the rules for that particular search engine, database, etc. Keep in mind, however, the general rules that we have gone over today are very helpful in most cases and...
Credits Slide #2 Question Marks http://www.inkcartridgeemporium.com/question_marks.jpg http://www.mediabistro.com/unbeige/original/joe-censored.jpg http://www.ysspromo.com/uploaded/images/QuestionGuy.jpg Slide #3 George Boole http://www.veganlibrarian.com/LIBR287/George_Boole.jpg Side #5 Boolean Operators http://www.academicworklife.org/images/search/search_boolean.gif Slide #6 “Boolean Remote” http://www.scs.carleton.ca/~lanthier/teaching/COMP1405/Notes/COMP1405_8/re mote.jpg Slide #20 “The End http://www.jeremyville.com/comicstrips/the_end/The_End.jpg
Another Strategy Called “Nesting” Uses Parentheses Is Related To Math Like a mathematical equation, a search statement is performed left to right. If parentheses are used, the parts of the search contained within the parentheses are performed first.
Without the parenthesis, the operators are performed in an illogical order so the search will return irrelevant results. For example: ethics and (gamble or bet) will return different results from ethics and gamble or bet.