X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=doc%2Fquerymodel.xml;h=3a3f781364c18f34d8ca197c1453277728869fb9;hb=3fbd2beb5c41de39604f27b39a9461335b2b176b;hp=82d25ec6a072ed011b76c004f72e2819cf3b7328;hpb=3b8c3227f359d5a4ff1b2df52139f1b88a01ce34;p=idzebra-moved-to-github.git diff --git a/doc/querymodel.xml b/doc/querymodel.xml index 82d25ec..3a3f781 100644 --- a/doc/querymodel.xml +++ b/doc/querymodel.xml @@ -1,11 +1,11 @@ - + Query Model - +
Query Model Overview - +
Query Languages @@ -29,7 +29,7 @@ - +
Prefix Query Format (PQF) Index Data has defined a textual representation in the @@ -41,12 +41,12 @@ parties developing Z39.50 software, and is often referred to as Prefix Query Notation, or in short PQN. See - for further explanations and + for further explanations and descriptions of Zebra's capabilities. - +
- +
Common Query Language (CQL) The query model of the type-1 RPN, @@ -59,11 +59,11 @@ Zebra can be configured to understand and map CQL to PQF. See . - +
- +
- +
Operation types Zebra supports all of the three different @@ -73,7 +73,7 @@ functionality and purpose of each is quite in order here. - +
Explain Operation The syntax of Z39.50/SRU queries is @@ -106,9 +106,9 @@ auto-configure a client user interface to the servers capabilities. - +
- + - +
Scan Operation The scan operation is a helper functionality, @@ -137,15 +137,15 @@ spelling of search terms, to auto-fill search boxes, or to display controlled vocabularies. - +
- +
- +
- - Prefix Query Format syntax and semantics +
+ RPN queries and semantics The PQF grammar is documented in the YAZ manual, and shall not be @@ -155,10 +155,10 @@ query parse tree. - - PQF tree structure +
+ RPN tree structure - The PQF parse tree - or the equivalent textual representation - + The RPN parse tree - or the equivalent textual representation in PQF - may start with one specification of the attribute set used. Following is a query tree, which @@ -169,7 +169,7 @@ complex query trees. - +
Attribute sets Attribute sets define the exact meaning and semantics of queries @@ -184,7 +184,7 @@ Attribute set - Short hand + PQF notation (Short hand) Status Notes @@ -192,7 +192,7 @@ - Explain + Explain exp-1 Special attribute set used on the special automagic IR-Explain-1 database to gain information on @@ -201,24 +201,24 @@ predefined - Bib1 + Bib-1 bib-1 Standard PQF query language attribute set which defines the semantics of Z39.50 searching. In addition, all of the - non-use attributes (types 2-11) define the hard-wired + non-use attributes (types 2-12) define the hard-wired Zebra internal query processing. default - GILS + GILS gils - Extension to the Bib1 attribute set. + Extension to the Bib-1 attribute set. predefined - +
Zebra Extension Rank Weight Attribute (type 9) Rank weight is a way to pass a value to a ranking algorithm - so @@ -1613,12 +1628,37 @@ Z> find @attr 2=102 @or @attr 9=30 @attr 1=4 utah @attr 9=20 utah - +
+ +
+ Zebra Extension Term Reference Attribute (type 10) + + Zebra supports the searchResult-1 facility. + If the Term Reference Attribute (type 10) is + given, that specifies a subqueryId value returned as part of the + search result. It is a way for a client to name an APT part of a + query. + + + + + Experimental. Do not use in production code. + + - - Zebra Extension Approximative Limit Attribute (type 11) +
+ + + +
+ Local Approximative Limit Attribute (type 11) - Zebra computes - unless otherwise configured - + Zebra computes - unless otherwise configured - the exact hit count for every APT (leaf) in the query tree. These hit counts are returned as part of the searchResult-1 facility in the binary encoded Z39.50 search @@ -1654,47 +1694,38 @@ Do not use approximative hit count limits in conjunction with relevance ranking, as re-sorting of the - result set obviosly only works when the entire result set has + result set only works when the entire result set has been processed. - - - This facility clashes with rank weight, because there all - documents in the hit lists need to be examined for scoring and - re-sorting. - It is an experimental - extension. Do not use in production code. - - - +
- - Zebra Extension Term Reference Attribute (type 10) +
+ Global Approximative Limit Attribute (type 12) - Zebra supports the searchResult-1 facility. - If the Term Reference Attribute (type 10) is - given, that specifies a subqueryId value returned as part of the - search result. It is a way for a client to name an APT part of a - query. + By default Zebra computes precise hit counts for a query as + a whole. Setting attribute 12 makes it perform approximative + hit counts instead. It has the same semantics as + estimatehits for the . - + The attribute (12) can occur anywhere in the query tree. + Unlike regular attributes it does not relate to the leaf (APT) + - but to the whole query. + - Experimental. Do not use in production code. - + Do not use approximative hit count limits + in conjunction with relevance ranking, as re-sorting of the + result set only works when the entire result set has + been processed. + - - - - +
+ +
- +
Zebra specific Scan Extensions to all Attribute Sets Zebra extends the Bib1 attribute types, and these extensions are @@ -1729,7 +1760,7 @@ - +
Zebra Extension Result Set Narrow (type 8) If attribute Result Set Narrow (type 8) @@ -1765,35 +1796,25 @@ - - - Experimental. Do not use in production code. - - - + + Zebra 2.0.2 and later is able to skip 0 hit counts. This, however, + is known not to scale if the number of terms to skip is high. + This most likely will happen if the result set is small (and + result in many 0 hits). + +
- +
Zebra Extension Approximative Limit (type 11) The Zebra Extension Approximative Limit (type 11) is a way to enable approximate hit counts for scan hit counts, in the same way as for search hit counts. - - - - Experimental and buggy. Definitely not to be used in production code. - - - - +
+
- +
Zebra special IDXPATH Attribute Set for GRS indexing The attribute-set idxpath consists of a single @@ -1815,7 +1836,7 @@ - +
IDXPATH Use Attributes (type = 1) This attribute set allows one to search GRS filter indexed @@ -1939,11 +1960,11 @@ - - +
+
- +
Mapping from PQF atomic APT queries to Zebra internal register indexes @@ -1955,7 +1976,7 @@ the named register. - +
Mapping of PQF APT access points Zebra understands four fundamental different types of access @@ -2088,10 +2109,10 @@ - +
- +
Mapping of PQF APT structure and completeness to register type @@ -2298,10 +2319,10 @@ contents. - - +
+
- +
Zebra Regular Expressions in Truncation Attribute (type = 5) @@ -2405,7 +2426,7 @@ Z> find @attr 1=4 @attr 5=102 @attr 2=102 "informat.* retrieval" - +
- +
- +
Server Side CQL to PQF Query Translation Using the @@ -2475,23 +2496,19 @@ Exhaustive information can be found in the Section "Specification of CQL to RPN mappings" in the YAZ manual. - - http://www.indexdata.dk/yaz/doc/tools.tkl#tools.cql.map, - and shall therefore not be repeated here. + , + and shall therefore not be repeated here. - - - +