DialogWeb Help:  What is Truncation?

Dialog searching is based on an exact match of a search term to an index entry. Truncation is a means of searching variant forms of a term. Truncation uses one or more question marks at the end of a search term to search on a word stem or incomplete term.

Word stems should be at least three characters long. Common stems, such as cat and com, should be avoided since the truncation of a short term may retrieve many irrelevant terms, for example, s cat? retrieves cat, catalog, catastrophe, and so forth.

Open Truncation
With open truncation you can truncate a search term by appending a question mark to the end of a term. For example, enter transport? and all records containing the word stem transport are retrieved, including such terms as transportation, transported, transporting, and transportable.

Restricted Truncation
To restrict the truncation, enter one question mark for each character you wish to allow. For example, enter transport??? and all records containing the word stem, transport, plus three characters are retrieved including transport and transporting. A question mark followed by a space and another question mark retrieves records containing the word stem and one additional character following the word stem. This strategy is frequently used to retrieve a specific search term in both its singular and plural forms.

Internal Truncation
A question mark can replace a character in a search term. For example, to retrieve records that contain the terms woman and women, enter s wom?n. More than one question mark can be inserted in a term, however, the terms retrieved will have one character for each question mark used. For example, enter s psych????ist and records containing the terms psychologist and psychiatrist are retrieved. You can also use internal truncation with open and restricted truncation. Internal truncation cannot be used to retrieve variations in spelling that result in words of different lengths, for example, color and colour.