X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=doc%2Fzebra.sgml;h=9bae27f4ce75eb6a7a8e71976fa7a82d28ff252d;hb=70961362d71c04daaf0b0feafe59e78d235eb116;hp=6774a64d76a828f5c80f64fe89e08b525b73d552;hpb=c55a1b30ba82e0343574574da5481cac2735a82b;p=idzebra-moved-to-github.git diff --git a/doc/zebra.sgml b/doc/zebra.sgml index 6774a64..9bae27f 100644 --- a/doc/zebra.sgml +++ b/doc/zebra.sgml @@ -1,13 +1,13 @@
Zebra Server - Administrators's Guide and Reference <author><htmlurl url="http://www.indexdata.dk/" name="Index Data">, <tt><htmlurl url="mailto:info@index.ping.dk" name="info@index.ping.dk"></> -<date>$Revision: 1.29 $ +<date>$Revision: 1.33 $ <abstract> The Zebra information server combines a versatile fielded/free-text search engine with a Z39.50-1995 frontend to provide a powerful and flexible @@ -159,9 +159,6 @@ data elements in records. *Port the system to Windows NT. <item> -Add index and data compression to save disk space. - -<item> Add more sophisticated relevance ranking mechanisms. Add support for soundex and stemming. Add relevance <it/feedback/ support. @@ -949,10 +946,11 @@ the client. The maximum PDU size is negotiated down to a maximum of <sect2>Search <p> -The supported query type are 1 and 101 All operators except PROXIMITY -are currently supported. Queries can be arbitrarily complex. Named -result sets are supported, and result sets can be used as operands -with no limitations. Searches may span multiple databases. +The supported query type are 1 and 101. All operators are currently +supported except that only proximity units of type "word" are supported +for the proximity operator. Queries can be arbitrarily complex. Named +result sets are supported, and result sets can be used as operands with +no limitations. Searches may span multiple databases. The server has full support for piggy-backed present requests (see also the following section). @@ -991,8 +989,127 @@ search. As a default, a single error (deletion, insertion, replacement) is accepted when terms are matched against the register contents. -<sect2>Present +Zebra interprets queries in one the following ways: +<descrip> +<tag>1 Phrase search</tag> + Each token separated by white space is truncated according to the + value of truncation attribute. If the completeness attribute + is <bf/complete subfield/ the search is directed to the phrase + register. For other completeness attribute values the term is split + into tokens according to the white-space specification in the + character map. Only records in which each token exists in the order + specified are matched. +<tag>2 Word search</tag> + The token is truncated according to the value of truncation attribute. + The completeness attribute is ignored. +<tag>3 Ranked search</tag> + Each token separated by white space is truncated according to the value + of truncation attribute. The completenss attribute is ignored. +<tag>4 Numeric relation</tag> + The token should consist of decimal digits. The integer is matched + against integers in the register according to the relation attribute. + The truncation - and the completenss attribute is ignored. +<tag>5 Document identifier</tag> + The token consists of exactly one document identifier. The + truncation - and the completeness attribute is ignored. +</descrip> + +For ranked searches the result sets are ranked and a score +is associated with each record. All other result sets from the +remaining four types are non-ranked. + +Combinations of the structure attribute and the relation attribute +determine how the query is interpreted. The two following tables +define how. + +<verb> + Structure Attribute (4) + none phrase(1) word(2) word list(6) + + none 1 1 2 3 + = (3) 1 1 2 3 + < (1) 4 4 4 4 +Relation <= (2) 4 4 4 4 +Attribute >= (4) 4 4 4 4 + (2) > (5) 4 4 4 4 + <> (6) - - - - + rel (102) 3 3 3 3 + other 1 1 2 3 + +</verb> +<verb> + Structure Attribute (4) + free-form- document- local- string + text text number + (105) (106) (107) (108) + none 3 3 5 1 + = (3) 3 3 5 1 + < (1) 4 4 5 4 + Relation <= (2) 4 4 5 4 + Attribute >= (4) 4 4 5 4 + (2) > (5) 4 4 5 4 + <> (6) - - 5 - + rel (102) 3 3 5 3 + other 3 3 5 1 + +</verb> + +<sect3>Regular expressions +<p> + +Each term in a query is interpreted as a regular expression if +the truncation value is either <bf/Regxp-1/ (102) or <bf/Regxp-2/ (103). +Both query types follow the same syntax with the operands: +<descrip> +<tag/x/ Matches the character <it/x/. +<tag/./ Matches any character. +<tag><tt/[/..<tt/]/</tag> Matches the set of characters specified; + such as <tt/[abc]/ or <tt/[a-c]/. +</descrip> +and the operators: +<descrip> +<tag/x*/ Matches <it/x/ zero or more times. Priority: high. +<tag/x+/ Matches <it/x/ one or more times. Priority: high. +<tag/x?/ Matches <it/x/ once or twice. Priority: high. +<tag/xy/ Matches <it/x/, then <it/y/. Priority: medium. +<tag/x|y/ Matches either <it/x/ or <it/y/. Priority: low. +</descrip> +The order of evaluation may be changed by using parentheses. + +If the first character of the <bf/Regxp-2/ query is a plus character +(<tt/+/) it marks the beginning of a section with non-standard +specifiers. The next plus character marks the end of the section. +Currently Zebra only supports one specifier, the error tolerance, +which consists one digit. + +Since the plus operator is normally a suffix operator the addition to +the query syntax doesn't violate the syntax for standard regular +expressions. + +<sect3>Query examples +<p> +Phrase search for <bf/information retrieval/ in the title-register: +<verb> + @attr 1=4 "information retrieval" +</verb> + +Ranked search for the same thing: +<verb> + @attr 1=4 @attr 2=102 "Information retrieval" +</verb> + +Phrase search with a regular expression: +<verb> + @attr 1=4 @attr 5=102 "informat.* retrieval" +</verb> + +Ranked search with a regular expression: +<verb> + @attr 1=4 @attr 5=102 @attr 2=102 "informat.* retrieval" +</verb> + +<sect2>Present <p> The present facility is supported in a standard fashion. The requested record syntax is matched against the ones supported by the profile of