From 4ab240934731700f437e2bf8cb695e4b5fc9c0dc Mon Sep 17 00:00:00 2001 From: Mike Taylor Date: Thu, 22 May 2003 16:57:28 +0000 Subject: [PATCH] Add documentation for CQL->RPN transformation's error-reporting --- doc/tools.xml | 185 +++++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 174 insertions(+), 11 deletions(-) diff --git a/doc/tools.xml b/doc/tools.xml index 7f1997c..56fe958 100644 --- a/doc/tools.xml +++ b/doc/tools.xml @@ -1,4 +1,4 @@ - + Supporting Tools @@ -182,16 +182,120 @@ Version 3 of the Z39.50 specification defines various encoding of terms. - Use the @term type, + Use @term type + string, where type is one of: general, - numeric, string - (for InternationalString), .. + numeric or string + (for InternationalString). If no term type has been given, the general form - is used which is the only encoding allowed in both version 2 - and 3 + is used. This is the only encoding allowed in both versions 2 and 3 of the Z39.50 standard. - PQF queries + + Using Proximity Operators with PQF + + + This is an advanced topic, describing how to construct + queries that make very specific requirements on the + relative location of their operands. + You may wish to skip this section and go straight to + the example PQF queries. + + + + + Most Z39.50 servers do not support proximity searching, or + support only a small subset of the full functionality that + can be expressed using the PQF proximity operator. Be + aware that the ability to express a + query in PQF is no guarantee that any given server will + be able to execute it. + + + + + + The proximity operator @prox is a special + and more restrictive version of the conjunction operator + @and. Its semantics are described in + section 3.7.2 (Proximity) of Z39.50 the standard itself, which + can be read on-line at + + + + In PQF, the proximity operation is represented by a sequence + of the form + +@prox exclusion distance ordered relation which-code unit-code + + in which the meanings of the parameters are as described in in + the standard, and they can take the following values: + + exclusion + 0 = false (i.e. the proximity condition specified by the + remaining parameters must be satisfied) or + 1 = true (the proximity condition specified by the + remaining parameters must not be + satisifed). + + distance + An integer specifying the difference between the locations + of the operands: e.g. two adjacent words would have + distance=1 since their locations differ by one unit. + + ordered + 1 = ordered (the operands must occur in the order the + query specifies them) or + 0 = unordered (they may appear in either order). + + relation + Recognised values are + 1 (lessThan), + 2 (lessThanOrEqual), + 3 (equal), + 4 (greaterThanOrEqual), + 5 (greaterThan) and + 6 (notEqual). + + which-code + known + or + k + (the unit-code parameter is taken from the well-known list + of alternatives described in below) or + private + or + p + (the unit-code paramater has semantics specific to an + out-of-band agreement such as a profile). + + unit-code + If the which-code parameter is known + then the recognised values are + 1 (character), + 2 (word), + 3 (sentence), + 4 (paragraph), + 5 (section), + 6 (chapter), + 7 (document), + 8 (element), + 9 (subelement), + 10 (elementType) and + 11 (byte). + If which-code is private then the + acceptable values are determined by the profile. + + + (The numeric values of the relation and well-known unit-code + parameters are taken straight from + the ASN.1 of the proximity structure in the standard.) + + + + PQF queries Queries using simple terms. @@ -227,8 +331,40 @@ Proximity. @prox 0 3 1 2 k 2 dylan zimmerman - - + + + Here the parameters 0, 3, 1, 2, k and 2 represent exclusion, + distance, ordered, relation, which-code and unit-code, in that + order. So: + + + exclusion = 0: the proximity condition must hold + + + distance = 3: the terms must be three units apart + + + ordered = 1: they must occur in the order they are specified + + + relation = 2: lessThanOrEqual (to the distance of 3 units) + + + which-code is ``known'', so the standard unit-codes are used + + + unit-code = 2: word. + + + So the whole proximity query means that the words + dylan and zimmerman must + both occur in the record, in that order, differing in position + by three or fewer words (i.e. with two or fewer words between + them.) The query would find ``Bob Dylan, aka. Robert + Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman'' + since the distance in this case is four. + + Specifying term type. @@ -243,8 +379,20 @@ @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109 + + + The last of these examples is a spatial search: in + the GILS attribute set, + access point + 2038 indicates West Bounding Coordinate and + 2030 indicates East Bounding Coordinate, + so the query is for areas extending from -114 degrees + to no more than -109 degrees. + + - + Common Command Language @@ -771,8 +919,23 @@ int cql_transform_buf(cql_transform_t ct, If conversion failed, cql_transform_buf - returns a non-zero error code; otherwise zero is returned - (conversion successful). + returns a non-zero SRW error code; otherwise zero is returned + (conversion successful). The meanings of the numeric error + codes are listed in the SRW specifications at + + + + If conversion fails, more information can be obtained by calling + +int cql_transform_error(cql_transform_t ct, char **addinfop); + + This function returns the most recently returned numeric + error-code and sets the string-pointer at + *addinfop to point to a string containing + additional information about the error that occurred: for + example, if the error code is 15 (``Illegal or unsupported index + set''), the additional information is the name of the requested + index set that was not recognised. If you wish to be able to produce a PQF result in a different -- 1.7.10.4