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Education Resources at SDSU Library

Databases 101

What is a library database? A library database is an electronic catalog or index that SDSU subscribes to that contains information.  These databases are organized so that you can search through a great deal of information easily.  The information within library databases vary but typically, they include articles and other information from print sources like magazines, academic journals, newspapers and reference books.

Databases have different topical coverage within them. Some databases are multidisciplinary and have information on many different topics. Other databases are specialized to one topical area like business, or psychology. It is important to keep this in mind when it comes time to pick which database to search in.  

Boolean Basics

Databases have a huge amount of information within them. To more effectively mine through this data, use the search syntax or searching rules to improve your search results.  This means you need to use the Boolean operators of: AND, OR, NOT to create search strings using your keywords.


  • AND
    • Tells the database to return results that include both the keywords.  Links different aspects of your research question together to find both concepts in the set of returned results.
    • Narrows your results.
  • OR
    • Tells the database to return results that include either of the keywords.
    • Links synonymous terms or concepts.
    • Expands your results.
  • NOT
    • Tells the database to return results that do not include a certain keyword.
    • Rids results of items that that contain a certain element of research topic.
    • Narrows your results

Advanced Search Techniques

Using Quotations

  • Requires keywords to be searched as a phrase.
  • Ex. Finds “Global warming” instead of the default AND between keywords: Global AND warmi

Using Parenthesis

  • Parenthesis allow you to create more complex search strings.
  • Especially useful when using OR operator in between similar concepts.
  • Ex. (ethics or morality) and cloning- Searches for articles with either ethics or morality AND the keyword cloning.

Using Truncation

  • Truncation, also called stemming, is a technique that broadens your search to include various word endings and spellings.
  • To use truncation, enter the root of a word and put the truncation symbol at the end.
  • Truncation symbols may vary by database; common symbols include: *, !, ?, or #
  • Examples:
    child* = child, childs, children, childrens, childhood
    genetic* = genetic, genetics, genetically

Turn Your Google Search Into a Database Search

You need to break down your topic into the most important elements to then create a search string. Before jumping into your research you should spend a few minutes brainstorming keywords to help form search strings about your topic.  You can think of keywords as how you might “tag” your topic.


  1. Google Search: What are the pros and cons of genetic cloning?
  2. Keywords: benefit, advantages, pros, negative, disadvantage, harm, genetic cloning, human cloning, clone, genetics.

Now that you have thought about some terms that might be in articles about your desired subject the trick is to create search strings that incorporate those keywords as well as the rules databases use to run their search algorithms.

Databases use search algorithms to mine thru the great amount of information the databases have. Therefore, it is important to use the search syntax or searching rules that will provide you with the best results.  This means you need to use the Boolean operators of: AND, OR, NOT to create search strings using your keywords.‚Äč

Search Examples

Putting it All Together:

Example 1. Topic: You are writing a paper looking at the movement for human rights in China.

  • Research Topic: What is the current status of human rights in China?
  • Keywords: human rights, civil rights, political rights, political freedom, social freedom, China, The People’s Republic of China.
  • Potential Database Search: (“human right*” or “civil right*”) and Chin*

Example 2.  You are writing a persuasive pro/con paper on the issue of corporate farming and animal rights.

  • Research Topic: What is a corporate farm and how are animal rights affected?
  • Keywords: factory farm, corporate farm, animal rights, animal welfare
  • Potential Database Search: (“animal right*” or “animal welfare”) and (“factory farm*” or “corporate farm*”).