Databases: Most of the search engine or databases often return thousands of results. So, to use search engines / databases effectively, it is essential to apply techniques that narrow results and push the most relevant pages to the top of the results list. Below are a number of strategies for boosting search engine / database performance. Without these strategies or techniques, finding what you need will be difficult task and any user by spending a few minutes clarifying his / her need, can increase the chances of finding relevant information over internet.
a) Search Strategies: To arrive at appropriate target, a user of a database or search engine should know about the search strategies that need to be followed. In the following paragraphs some such steps are listed out.
i) Step 1: Framing the need by sentence: Frame your need by appropriate sentences. For example: One need information on “Digital libraries of India”
ii) Step 2: Identify Keywords: Find out the keywords or main concepts in the statement. In the above example the keywords will be <digital library> <India>.
iii) Step 3: Select Synonyms and Variant Word Forms: Find out the synonyms / alternate spellings, and variant word forms of each keyword. In the above example the synonyms of <digital library> will be <Virtual Library>, <Library without wall>, and <Institutional Repository>.
iv) Step 4: Combine Synonyms, Keywords, and Variant Word Forms With Boolean Operators: Now combine synonyms with Boolean OR. Place parentheses around OR statements. So, in the above example, the search terms will be: ‘Digital Library or virtual library or Library without wall or Institutional repository’ and India. Please note here that some search engine consider “OR” as “+”, “AND” as “*” and “NOT” and “-“. You should combine your words accordingly.
When you are unaware of the complete word you can use the truncation facility with an asterisk symbol (*). Eg. Librar* to retrieve the document that contain the word library, librarian, and so on.
v) Step 5: Check Your Spelling: Search engines return websites with words that match your keywords. If you misspell a keyword, your results will contain websites where that word is also misspelled. So at the last step check all your spellings.
b) Boolean Operators: Boolean logic is a complete system for logical operations. It was named after George Boole, an English mathematician at University College Cork who first defined an algebraic system of logic in the mid 19th century.
i) Boolean AND: Connecting search terms with AND tells the search engine to retrieve web pages containing ALL the keywords. So, AND considerably limit the search results.
Example: OCLC and Classify
Please note that the star sign (*) is the equivalent of AND in some search engine (Google).
ii) Boolean OR: Linking search terms with OR tells the search engine to retrieve web pages containing ANY and ALL keywords. When OR is used, the search engine returns pages with a single keyword, several keywords, and all keywords. So, OR expand the search results.
Example: Librarian or Library
Please note that in many search engines, the plus symbols can be used as alternatives to Boolean OR.
iii) Boolean NOT: NOT tells the search engine to retrieve web pages containing one keyword but not the other.
Example: OCLC not DDC
The above example instructs the search engine to return web pages about OCLC but not web pages about the "DDC". One can use NOT when he/she have a keyword that has multiple meanings. In some search engines, the minus symbols (-) is used as alternatives to Boolean NOT.
The AltaVista's Simple Search requires the use of plus and minus rather than AND, OR, and AND NOT. However you can use AltaVista's Advanced Search for full Boolean (AND, OR, and NOT) searches.
iv) Complex Search Using Boolean Logic: Example: Library AND (Acquisition OR Classification). This expression will search for results matching the document of Library acquisition or classification.
c) Some Other Search Techniques: Some other popular search techniques that can be used over the web in many search engines are listed bellow.
i) Phrase Searching: Surrounding a group of words with double quotes tells the search engine to only retrieve documents in which those words appear side-by-side. Phrase searching is a powerful search technique for significantly narrowing your search results, and it should be used as often as possible.
Example: “Five Laws of Library Science”
ii) Phrase Searching With Boolean Operators: You can also combine a phrase search with additional keywords using Boolean logic.
Example: “Five Laws of Library Science” * Dr. S R Ranganathan
iii) Title Search: Field searching is one of the most effective techniques for narrowing results and getting the most relevant websites listed at the top of the results page. A web page is composed of a number of fields, such as title, domain, host, URL, and link. Searching effectiveness increases as you combine field searches with phrase searches and Boolean logic. For example, if you wanted to find information about Five Laws of Library Science and Dr. S R Ranganathan, you could try the following search:
Example: +title:"Five Laws of Library Science" + Dr. S R Ranganathan
Example: title:"Five Laws of Library Science" and Dr. S R Ranganathan
The above title search example instructs the search engine to return web pages where the phrase Five Laws of Library Science appears in the title and the words Dr. S R Ranganathan appear somewhere on the page. Please note that like plus and minus, there is no space between the colon (:) and the keyword.
iv) Domain Search: The domain search allows you to limit results to certain domains such as websites from the United Kingdom (.uk), educational institutions (.edu), or government sites (.gov).
Example: +domain:in +title:"Guwahati"
Example: domain:in and title:"Guwahati"
Example: +domain:in +title:"Guwahati" * Dispur
Example: domain:in and title:"Guwahati" * Dispur
v) Host Search: The host search comes in handy when you need to find something located at a large site that does not have an internal search engine (if the site has an internal search engine then for the best result you should use it). With the host search technique, you can search all the pages at a website (contained in the engine's database) for keywords or phrases of interest.
Example: +host:www.kkhsou.org +"PhD"
Example: host:www.kkhsou.org and "PhD"
vi) URL Search: The URL search limits search results to web pages where the keyword appears in the URL or website address. A URL search can narrow very broad results to web pages devoted to the keyword topic.
Example: +url:NET +title:UGC
Example: url:NET and title:UGC
vii) Link Search: Use the link search when you want to know what websites are linked to a particular site of interest. For example, if you have a home page and you are wondering if anyone has put a link to your page on their website, use the Link search. Researchers use link searches for conducting backward citations.
In conducting a search over any search engine / database please note that they have some variants. The variants can be viewed from the following angles-
i) Capital Letters: Most search engines interpret lower case letters as either upper or lower case. Thus, if you want both upper and lower case occurrences returned, type your keywords in all lower case letters. However, if you want to limit your results to initial capital letters (e.g., "George Washington") or all upper case letters, type your keywords that way.
ii) Plural Forms: Most search engines interpret singular keywords as singular or plural. If you want plural forms only, make your keywords plural, otherwise ignore it.
iii) Alternate Spellings: A few search engines support truncation or wildcard features that allow variations in spelling or word forms. The asterisk (*) symbol tells the search engine to return alternate spellings for a word at the point that the asterisk appears. For example, catalog* returns web pages with catalogue and cataloguer.
d) Practicing with Search Engine: Now let’s explore some popular search engine in terms of the facilities they provide for searching their databases.
i) Google (http://www.google.com/): Google has the largest database at 1.5 billion pages and is very adept at returning relevant results. Google uses mathematical formulas to rank a web page based on the number of "important" pages that link to it.
Google supports OR (in all caps), but does not support full Boolean AND NOT. However, it does allow the implied Boolean minus sign (-). When multiple keywords are entered, all keywords are treated as "AND" queries. Because Google automatically returns pages that include all keywords, the plus sign (+) and the operator AND are not necessary. Also, quotation marks for phrase searching are not required as Google returns pages with keywords in close proximity.
Google supports link searching and title, domain, and host searching through its Advanced Search page. It provides domain searching on .gov and .mil sites with a special "Uncle Sam" database. Using the Image Search database, News Search database, or Discussion Group Search database, visitors can search for pictures / graphics, news articles, and newsgroup postings. Finally, unlike other search engines, Google offers a cached copy of each result. The cached copy can be especially helpful if the site's server is down or the web page is no longer available.
ii) Hot Bot (http://www.hotbot.com/): HotBot has an index of about 500 million pages. It supports implied Boolean logic (+/-), full Boolean logic (and, or, and not), and truncation (*). HotBot also offers phrase, title, and domain searches as well as several media-type searches such as audio, video, and images.
iii) Alta Vista (http://www.altavista.com): AltaVista offers both a Simple Search and an Advanced Search page. Simple Search requires the use of implied Boolean logic (plus and minus), while Advanced Search requires full Boolean logic (and, or, and not). Both the Simple and Advanced pages support phrase searching, field searching (title, domain, host, URL, and link searches), and truncation (*). AltaVista offers several specialty search engines including an image finder, an MP3/audio finder, a video finder, and a people finder.
AltaVista offers a number of powerful search features not found elsewhere. One very effective tool available on the Advanced Search page is the NEAR search. A NEAR search limits results to pages where keywords appear within 10 words of each other. This can be extremely helpful in situations where an AND search produces too many results and a phrase search (" ") produces too few results.
Example: "heart disease" near prevent
Example: heart disease near prevent
iv) All The Web (http://www.alltheweb.com/): All the Web/FAST Search supports implied Boolean logic (+/-) and phrase searching on the Basic Search page. The Advanced Search page also offers title, domain, host, URL and link searches.
e) Let Us Sum Up: The more care and thought you put into your search strategy, the more relevant your search results will be. A well designed search strategy will save you time in the long run, allow you to search for information in many different places, and help you to find a larger amount of relevant information. Different strategies work better for different people. There is no need to follow every step listed above. Try a few different techniques to see what works best for you.