Query Language

You can search for any word or phrase on a Web site by typing the word or phrase into a query form and clicking the button to execute the query (for example, the Execute Query button on the sample query form). This section covers the following topics:

• Boolean and Proximity Operators: Shows how to make more precise queries by inserting Boolean and proximity operators.
• Wildcards: Helps you find pages containing words similar to a given word.
• Free-Text Queries: Describes how to formulate a query based on the meaning of a phrase rather than the exact wording.
• Vector Space Queries: Explains how to get query results that match a list of words and phrases.

Searches produce a list of files that contain the word or phrase no matter where they appear in the text. This list gives the rules for formulating queries:

• Consecutive words are treated as a phrase; they must appear in the same order within a matching document.

• Queries are case-insensitive, so you can type your query in uppercase or lowercase.

• You can search for any word except for those in the exception list (for English, this includes a, an, and, as, and other common words), which are ignored during a search.

• Words in the exception list are treated as placeholders in phrase and proximity queries. For example, if you searched for “Word for Windows”, the results could give you “Word for Windows” and “Word and Windows”, because for is a noise word and appears in the exception list.

• Punctuation marks such as the period (.), colon (:), semicolon (;), and comma (,) are ignored during a search.

• To use specially treated characters such as &, |, ^, #, @, $, (, ), in a query, enclose your query in quotation marks (“).

• To search for a word or phrase containing quotation marks, enclose the entire phrase in quotation marks and then double the quotation marks around the word or words you want to surround with quotes. For example, “World-Wide Web or ““Web””” searches for World-Wide Web or “Web”.

• You can insert Boolean operators (AND, OR, and NOT) and the proximity operator (NEAR) to specify additional search information.

• The wildcard character (*) can match words with a given prefix. The query esc* matches the terms “ESC,” “escape,” and so on.

• Free-text queries can be specified without regard to query syntax.

• Vector space queries can be specified.

Boolean and Proximity Operators

Boolean and proximity operators can create a more precise query.

Hints:

• You can add parentheses to nest expressions within a query. The expressions in parentheses are evaluated before the rest of the query.

• Use double quotes (“) to indicate that a Boolean or NEAR operator keyword should be ignored in your query. For example, “Abbott and Costello” will match pages with the phrase, not pages that match the Boolean expression. In addition to being an operator, the word and is a noise word in English.

• The NEAR operator is similar to the AND operator in that NEAR returns a match if both words being searched for are in the same page. However, the NEAR operator differs from AND because the rank assigned by NEAR depends on the proximity of words. That is, the rank of a page with the searched-for words closer together is greater than or equal to the rank of a page where the words are farther apart. If the searched-for words are more than 50 words apart, they are not considered near enough, and the page is assigned a rank of zero.

• The NOT operator can be used only after an AND operator in content queries; it can be used only to exclude pages that match a previous content restriction. For property value queries, the NOT operator can be used apart from the AND operator.

• The AND operator has a higher precedence than OR. For example, the first three queries are equal, but the fourth is not:

  a AND b OR c
  c OR a AND b
  c OR (a AND b)
  (c OR a) AND b

Note   The symbols (&, |, !, ~) and the English keywords AND, OR, NOT, and NEAR work the same way in all languages supported by Index Server. Localized keywords are also available when the browser locale is set to one of the following six languages:

Note   The NEAR operator can be applied only to words or phrases.

Wildcards

Wildcard operators help you find pages containing words similar to a given word.

Free-Text Queries

The query engine finds pages that best match the words and phrases in a free-text query. This is done by automatically finding pages that match the meaning, not the exact wording, of the query. Boolean, proximity, and wildcard operators are ignored within a free-text query. Free-text queries are prefixed with $contents.

Vector Space Queries

The query engine supports vector space queries. Vector queries return pages that match a list of words and phrases. The rank of each page indicates how well the page matched the query.

• Components in vector queries are separated by commas.
• Components in vector queries can be weighted by using the [weight] syntax.
• Pages returned by vector queries do not necessarily match every term in the query.
• Vector queries work best when the results are sorted by rank.