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.
• Property Value Queries: Tells how to query for the property values of a file.
• Query Examples: Gives examples of various queries.
• List of Property Names: Lists and describes property names always available for queries.

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.
• ActiveX™ (OLE) and file attribute property value queries can be issued.

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.

Property Value Queries

With property value queries, you can find files that have property values that match a given criteria. The properties over which you can query include basic file information like file name and file size, and ActiveX properties including the document summary (information) that is stored in files created by ActiveX-aware applications.

There are two types of property queries:

• Relational property queries consist of an “at” character (@), a property name, a relational operator, and a property value. For example, to find all of the files larger than one million bytes, issue the query @size > 1000000.
• Regular expression property queries consist of a number sign (#), a property name, and a regular expression for the property value. For example, to find to find all of the video (.avi) files, issue the query #filename *.avi. Regular expressions will never match the special properties contents (#contents) and all (#all). Properties that are not retrievable at query time cannot be used in # queries. these include HTML META properties not stored in the property cache.

This section covers the following topics:

• Property Names
• Relational Operators
• Property Values

Property Names

Property names are preceded by either the “at” (@) or number sign (#) character. Use @ for relational queries, and # for regular expression queries.

If no property name is specified, @contents is assumed.

Properties available for all files include:

ActiveX property values can also be used in queries. Web sites with files created by most ActiveX-aware applications can be queried for these properties:

For a complete list of property names, see the List of Property Names later on this page.

Relational Operators

Relational operators are used in relational property queries.

Property Values

• Be sure to use the pound (#) character before the property name when using a regular expression in a property value, and an “at” (@) character otherwise. The equal (=) relational operator is assumed for regular-expression queries.
• File name (#filename) is the only property that efficiently supports regular expressions with wildcards to the left of text.
• Date and time values are of the form yyyy/mm/dd hh:mm:ss or yyyy-mm-dd hh:mm:ss. The first two characters of the year and the entire time can be omitted. If you omit the first two characters of the year, then 29 or less is interpreted as the year 2000, and 30 or greater is interpreted as the year 1900. All dates and times are in Greenwich Mean Time (GMT).
• Dates and times relative to the current time can be expressed with a minus (-) character followed by zero or by more integer unit and time unit pairs. Time units are expressed as: (y) for years, (m) for months, (w) for weeks, (d) for days, (h) for hours, (n) for minutes, and (s) for seconds. A three-digit millisecond value can be optionally specified after the seconds value in date expressions. For example, 1997/12/8 10:10:03:452
• Currency values are of the form x.y, where x is the whole value amount and y is the fractional amount. There is no assumption about units.
• Boolean values are (t) or (true) for TRUE and (f) or (false) for FALSE.
• Vectors (VT_VECTOR) are expressed as an opening brace ({), followed by a comma-separated list of values, then a closing brace (}).
• Single-value expressions that are compared against vectors are expressed as a relational operator, then a (^a) for all of or a (^s) for some of.
• Numeric values can be in decimal or hexadecimal (preceded by 0x).
• The contents property does not support relational operators. If a relational operator is specified, no results will be found. For example, @contents Microsoft will find documents containing Microsoft, but @contents=Microsoft will find none.

Regular Expressions

Regular expressions in property queries are defined as follows:

• Any character except asterisk (*), period (.), question mark (?), and vertical bar (|) defaults to matching just itself.
• Regular expressions can be enclosed in matching quotes (“), and must be enclosed in quotes if they contain a space ( ) or closing parenthesis ()).
• The characters *, ., and ? behave as they behave in Windows; they match any number of characters, match (.) or end of string, and match any one character, respectively.
• The character | is an escape character. After |, the following characters have special meaning:

( opens a group. Must be followed by a matching ).


) closes a group. Must be preceded by a matching (.


[ opens a character class. Must be followed by a matching (un-escaped) ].


{ opens a counted match. Must be followed by a matching }.


} closes a counted match. Must be preceded by a matching {.


, separates OR clauses.


* matches zero or more occurrences of the preceding expression.


? matches zero or one occurrences of the preceding expression.


+ matches one or more occurrences of the preceding expression.


Anything else, including |, matches itself.


• Between square brackets ([]) the following characters have special meaning:

^ matches everything but following classes. Must be the first character.


] matches ]. May only be preceded by ^, otherwise it closes the class.


- range operator. Preceded and followed by normal characters.


Anything else matches itself (or begins or ends a range at itself).


• Between curly braces ({}) the following syntax applies:

|{m|} matches exactly m occurrences of the preceding expression. (0 < m < 256).


|{m,|} matches at least m occurrences of the preceding expression. (1 < m < 256).


|{m,n|} matches between m and n occurrences of the preceding expression, inclusive. (0 < m < 256, 0 < n < 256).


• To match *, ., and ?, enclose them in brackets (for example, |[*]sample will match “*sample”).

Query Examples

List of Property Names

These properties are always available for queries. Additional properties may also be available depending on the configuration of the Web server.

Defining New Property Names

To define properties that are not in the previous list, you must list them in a [Names] section in the .idq file. To use these properties in a restriction, sort specification, or as a retrieved column, you have define them in the .idq file, using the following format:

[Names]
#Properties that are not in the standard list
Propertyname ( Datatype ) = GUID ["Name" | propid]

In the syntax, "Name" is the property name ("Sales" in the following example), and propid is the property ID in hexadecimal. Note that you need to surround the friendly name with quotation marks, but the property ID does not take quotation marks.

For example, suppose you want to define an HTML meta tag as a property name that somebody can search for. The property you want to define is Sales.

To define the Sales property

1. In the .idq file, under the [Names] section, add the following line.

MetaDescription(DBTYPE_WSTR) = d1b5d3f0-c0b3-11cf-9a92-00a0c908dbf1 "Sales"


The GUID number comes from the MetaTagClsid parameter in the registry, at the following location:


HKEY_LOCAL_MACHINE
\SYSTEM
 \CurrentControlSet
  \Control
   \HtmlFilter
    \MetaTagClsid

2. Then, in the HTML files where you want the tag to appear, define the meta description.

For example, say you want to search for all files that give sales projections for the future:


In File1.htm:


<META NAME="Sales" CONTENT="Projections for 1998">


In File2.htm:


<META NAME="Sales" CONTENT="Projections for 1999">


In File3.htm:


<META NAME="Sales" CONTENT="Sales in 1997">

Note   Be sure to add your META NAME tags between the <head> and </head> HTML tags at the beginning of the file.

You can now search for all files that show sales projections. Send the following query:

@metadescription projections

This query returns all the files with the word projections in the CONTENT field of the meta tag. In this example, File1.htm and File2.htm are returned.

But suppose you want to search for sales by year, for example a list of sales in 2000. Send the following query:

@metadescription 2000

File3.htm is returned.