Home Information Skills Databases Advanced Search Techniques II

Information Skills

Advanced Search Techniques

Proximity, Truncation and Wild Cards

The power of Boolean searching can be extended further by proximity, truncation and wild card operators. Proximity searching allows you to specify that records found by your search contain one search term near another. If, for example, you are interested in red cars, a search string such as

may return irrelevant records because red is a very general adjective and could describe many other things in a record. The near operator requires that a record has terms close together in the text, making it more likely that there is a meaningful link between the terms in the record. Therefore one would use the search string:

The syntax used for truncation varies amongst databases; e.g. sometimes next is used rather then near - you should check the databases' help pages to find out if and how proximity can be used.

Truncation allows you to search for all the variants of a word without having to specify them all in your search string. It is very useful to take into account plural and singular forms of a noun. For example,

asks the computer to search for both car and cars, or any word beginning with car such as carriage or carburettor. So, as with the not operator you have to be careful when using this operator or you may get a lot of irrelevant records. Think about how many words might start with a root such as car before using truncation. If you simply wish to include both the singular and the plural forms of a noun in your search you might be better off using the or operator:

As for proximity, the syntax used for truncation varies amongst databases- you should check the databases' help pages to find out if and how truncation can be used.

Wildcards are rather like truncation, but rather than allowing for variation at the end of a word, it allows for variation in a character in the middle of a word. Wild cards are especially useful for taking into account variations in spelling. For example, many words can be spelt with an s or a z, e.g. realise/realize. You could use the or operator to get around this, but wild cards are much neater:

In the example above, any character can appear between the i and e. Again, syntax can vary between databases, sometimes ? is used - check the help pages!

Next: Combining Operators Using Parenthesis »