The Exopaedia offers the following advanced search modes:
- Boolean Search
- Natural Language Search
- Multi-criterion Search - available in the near future.
What: Boolean search is a Full Text Search facility that allows one to use Boolean operators, truncation, as well as some additional operators that influence the 'weight' of the results. Say, e.g. you want to find articles with regard to the Pleiades or Pleiadians, but not those that involve Billy Meier. Then you could use the following query: +pleiad* -meier, which means that the article must contain words that start with pleiad, but it is not allowed to contain the word meier. Boolean search is case insensitive. The available operators are described below.
By default (when neither
-is specified) the word is optional, but the rows that contain it will be rated higher. [In other words, "no operator" functions as a logical OR if more than 1 word is present].
- A leading plus sign indicates that this word must be present in every row returned.
- A leading minus sign indicates that this word must not be present in any row returned.
These two operators are used to change a word's contribution to the
relevance value that is assigned to a row. The
>operator increases the contribution and the
<operator decreases it. See the example below.
- Parentheses are used to group words into subexpressions. Parenthesized groups can be nested.
A leading tilde acts as a negation operator, causing the word's
contribution to the row relevance to be negative. It's useful for marking
noise words. A row that contains such a word will be rated lower than
others, but will not be excluded altogether, as it would be with the
- An asterisk is the truncation operator. Unlike the other operators, it should be appended to the word.
- A phrase that is enclosed within double quote (`"') characters matches only rows that contain the phrase literally, as it was typed.
Natural Language Search
What:Natural language search uses the same principles as traditional search engines on the Internet. The results of a search are weighted according to the number of hits within the same document. "Noise" (i.e. the amount of irrelevant hits) is reduced by using special algorithms.