Index: doc/src/sgml/func.sgml =================================================================== RCS file: /projects/cvsroot/pgsql/doc/src/sgml/func.sgml,v retrieving revision 1.377 diff -u -r1.377 func.sgml --- doc/src/sgml/func.sgml 7 Apr 2007 03:58:08 -0000 1.377 +++ doc/src/sgml/func.sgml 10 Apr 2007 11:51:34 -0000 @@ -8107,20 +8107,56 @@ a database system. These capabilities include import/export, indexing, searching, transforming, and XML to SQL mapping. PostgreSQL supports some - but not all of these XML capabilities. For an - overview of XML use in databases, see . + but not all of these XML capabilities. One of such capability + is xpath function which allows to evaluate XPath 1.0 + expressions against any XML value. For an overview of XML use in databases, + see . + + <literal>xpath</literal> + + + xpath + + + +xpath(xpath, xml, array) + + + + The function xpath evaluates XPath expression against + XML value and produces an array of XML values as a result. The third + argument of the function is an array of namespace mappings. This array + should be two-dimentional array with the length of the second axis being + equal to 2 (e.g., it should be an array of arrays, every of which constists + of exactly 2 elements, name and URI). + + + + Example: +test', ARRAY[ARRAY['my', 'http://example.com']]); + xpath +-------- + {test} +(1 row) +]]> + + + + + Other capabilities + Indexing - contrib/xml2/ functions can be used in expression - indexes to index specific XML fields. To index the - full contents of XML documents, the full-text + To improve performance of XPath evaluation, one can use functional indexes + over xpath with constant XPath expression. + To index the full contents of XML documents, the full-text indexing tool contrib/tsearch2/ can be used. Of course, Tsearch2 indexes have no XML awareness so additional contrib/xml2/ checks should be added to @@ -8134,9 +8170,10 @@ - XPath searches are implemented using contrib/xml2/. - It processes XML text documents and returns results - based on the requested query. + The basic XPath function is xpath which is built in. + Additional XPath functions are implemented using + contrib/xml2/. + @@ -8165,6 +8202,8 @@ + + Index: src/test/regress/sql/xml.sql =================================================================== RCS file: /projects/cvsroot/pgsql/src/test/regress/sql/xml.sql,v retrieving revision 1.14 diff -u -r1.14 xml.sql --- src/test/regress/sql/xml.sql 22 Mar 2007 20:26:30 -0000 1.14 +++ src/test/regress/sql/xml.sql 10 Apr 2007 11:51:34 -0000 @@ -147,9 +147,9 @@ -- Text XPath expressions evaluation -SELECT xmlpath('/value', data) FROM xmltest; -SELECT xmlpath(NULL, NULL) IS NULL FROM xmltest; -SELECT xmlpath('', ''); -SELECT xmlpath('//text()', 'number one'); -SELECT xmlpath('//loc:piece/@id', 'number one', ARRAY[ARRAY['loc'], ARRAY['http://127.0.0.1']]); -SELECT xmlpath('//b', 'one two three etc'); +SELECT xpath('/value', data) FROM xmltest; +SELECT xpath(NULL, NULL) IS NULL FROM xmltest; +SELECT xpath('', ''); +SELECT xpath('//text()', 'number one'); +SELECT xpath('//loc:piece/@id', 'number one', ARRAY[ARRAY['loc', 'http://127.0.0.1']]); +SELECT xpath('//b', 'one two three etc'); Index: src/include/catalog/pg_proc.h =================================================================== RCS file: /projects/cvsroot/pgsql/src/include/catalog/pg_proc.h,v retrieving revision 1.454 diff -u -r1.454 pg_proc.h --- src/include/catalog/pg_proc.h 2 Apr 2007 03:49:40 -0000 1.454 +++ src/include/catalog/pg_proc.h 10 Apr 2007 11:51:34 -0000 @@ -4114,9 +4114,9 @@ DATA(insert OID = 2938 ( database_to_xml_and_xmlschema PGNSP PGUID 12 100 0 f f t f s 3 142 "16 16 25" _null_ _null_ "{nulls,tableforest,targetns}" database_to_xml_and_xmlschema - _null_ )); DESCR("map database contents and structure to XML and XML Schema"); -DATA(insert OID = 2931 ( xmlpath PGNSP PGUID 12 1 0 f f f f i 3 143 "25 142 1009" _null_ _null_ _null_ xmlpath - _null_ )); +DATA(insert OID = 2931 ( xpath PGNSP PGUID 12 1 0 f f t f i 3 143 "25 142 1009" _null_ _null_ _null_ xpath - _null_ )); DESCR("evaluate XPath expression, with namespaces support"); -DATA(insert OID = 2932 ( xmlpath PGNSP PGUID 14 1 0 f f f f i 2 143 "25 142" _null_ _null_ _null_ "select pg_catalog.xmlpath($1, $2, NULL)" - _null_ )); +DATA(insert OID = 2932 ( xpath PGNSP PGUID 14 1 0 f f t f i 2 143 "25 142" _null_ _null_ _null_ "select pg_catalog.xpath($1, $2, ''{}''::_text)" - _null_ )); DESCR("evaluate XPath expression"); /* uuid */ Index: src/include/utils/xml.h =================================================================== RCS file: /projects/cvsroot/pgsql/src/include/utils/xml.h,v retrieving revision 1.18 diff -u -r1.18 xml.h --- src/include/utils/xml.h 1 Apr 2007 09:00:26 -0000 1.18 +++ src/include/utils/xml.h 10 Apr 2007 11:51:34 -0000 @@ -36,7 +36,7 @@ extern Datum texttoxml(PG_FUNCTION_ARGS); extern Datum xmltotext(PG_FUNCTION_ARGS); extern Datum xmlvalidate(PG_FUNCTION_ARGS); -extern Datum xmlpath(PG_FUNCTION_ARGS); +extern Datum xpath(PG_FUNCTION_ARGS); extern Datum table_to_xml(PG_FUNCTION_ARGS); extern Datum query_to_xml(PG_FUNCTION_ARGS); Index: src/backend/utils/adt/xml.c =================================================================== RCS file: /projects/cvsroot/pgsql/src/backend/utils/adt/xml.c,v retrieving revision 1.42 diff -u -r1.42 xml.c --- src/backend/utils/adt/xml.c 6 Apr 2007 04:21:43 -0000 1.42 +++ src/backend/utils/adt/xml.c 10 Apr 2007 11:51:34 -0000 @@ -2996,12 +2996,12 @@ * As we have no support of XQuery sequences yet, this functions seems * to be the most useful one (array of XML functions plays a role of * some kind of substritution for XQuery sequences). - + * * Workaround here: we parse XML data in different way to allow XPath for * fragments (see "XPath for fragment" TODO comment inside). */ Datum -xmlpath(PG_FUNCTION_ARGS) +xpath(PG_FUNCTION_ARGS) { #ifdef USE_LIBXML ArrayBuildState *astate = NULL; @@ -3013,11 +3013,11 @@ int32 len, xpath_len; xmlChar *string, *xpath_expr; bool res_is_null = FALSE; - int i; + int i, res_nitems; xmltype *data; text *xpath_expr_text; ArrayType *namespaces; - int *dims, ndims, ns_count = 0, bitmask = 1; + int *dims, ndim, ns_count = 0, bitmask = 1; char *ptr; bits8 *bitmap; char **ns_names = NULL, **ns_uris = NULL; @@ -3025,32 +3025,30 @@ bool typbyval; char typalign; - /* the function is not strict, we must check first two args */ - if (PG_ARGISNULL(0) || PG_ARGISNULL(1)) - PG_RETURN_NULL(); - xpath_expr_text = PG_GETARG_TEXT_P(0); data = PG_GETARG_XML_P(1); + namespaces = PG_GETARG_ARRAYTYPE_P(2); - /* Namespace mappings passed as text[]. - * Assume that 2-dimensional array has been passed, - * the 1st subarray is array of names, the 2nd -- array of URIs, - * example: ARRAY[ARRAY['myns', 'myns2'], ARRAY['http://example.com', 'http://example2.com']]. + /* + * Namespace mappings are passed as text[]. + * If empty array is passed (ndim = 0, "0-dimentional"), then there is no namespace mappings. + * Else, 2-dimentional array with length of the second axis being equal to 2 should be passed, + * i.e. every subarray contain 2 elements, the first element defining name, the second one -- URI. + * Example: ARRAY[ARRAY['myns', 'http://example.com'], ARRAY['myns2', 'http://example2.com']]. */ - if (!PG_ARGISNULL(2)) + ndim = ARR_NDIM(namespaces); + if (ndim != 0) { - namespaces = PG_GETARG_ARRAYTYPE_P(2); - ndims = ARR_NDIM(namespaces); dims = ARR_DIMS(namespaces); /* Sanity check */ - if (ndims != 2) + if (ndim != 2 || dims[1] != 2) ereport(ERROR, (errmsg("invalid array passed for namespace mappings"), - errdetail("Only 2-dimensional array may be used for namespace mappings."))); + errdetail("Only 2-dimentional array with length of the second axis being equal to 2 may be used for namespace mappings."))); Assert(ARR_ELEMTYPE(namespaces) == TEXTOID); - ns_count = ArrayGetNItems(ndims, dims) / 2; + ns_count = ArrayGetNItems(ndim, dims) / 2; /* number of NS mappings */ get_typlenbyvalalign(ARR_ELEMTYPE(namespaces), &typlen, &typbyval, &typalign); ns_names = (char **) palloc(ns_count * sizeof(char *)); @@ -3058,18 +3056,17 @@ ptr = ARR_DATA_PTR(namespaces); bitmap = ARR_NULLBITMAP(namespaces); bitmask = 1; - for (i = 0; i < ns_count * 2; i++) { if (bitmap && (*bitmap & bitmask) == 0) - ereport(ERROR, (errmsg("neither namespace nor URI may be NULL"))); /* TODO: better message */ + ereport(ERROR, (errmsg("neither namespace nor URI may be NULL"))); else { - if (i < ns_count) - ns_names[i] = DatumGetCString(DirectFunctionCall1(textout, + if (i % 2 == 0) + ns_names[i / 2] = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(ptr))); else - ns_uris[i - ns_count] = DatumGetCString(DirectFunctionCall1(textout, + ns_uris[i / 2] = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(ptr))); ptr = att_addlength_pointer(ptr, typlen, ptr); ptr = (char *) att_align_nominal(ptr, typalign); @@ -3093,31 +3090,38 @@ if (xpath_len == 0) ereport(ERROR, (errmsg("empty XPath expression"))); - if (xmlStrncmp((xmlChar *) VARDATA(data), (xmlChar *) "...) and extend XPath expression accordingly. To do it, throw away + * XML prolog, if any. + */ + if ((len > 4) && xmlStrncmp((xmlChar *) VARDATA(data), (xmlChar *) "' != (VARDATA(data))[i]))) + i++; + + if (i == len) + xml_ereport(ERROR, ERRCODE_INTERNAL_ERROR, + "could not parse XML data"); + + ++i; + string = xmlStrncatNew((xmlChar *) "", (xmlChar *) VARDATA(data) + i, len - i); } else - { - /* use "..." as dummy root element to enable XPath for fragments */ - /* TODO: (XPath for fragment) find better solution to work with XML fragment! */ string = xmlStrncatNew((xmlChar *) "", (xmlChar *) VARDATA(data), len); - string = xmlStrncat(string, (xmlChar *) "", 5); - len += 7; - xpath_expr = xmlStrncatNew((xmlChar *) "/x", (xmlChar *) VARDATA(xpath_expr_text), xpath_len); - len += 2; - } + + string = xmlStrncat(string, (xmlChar *) "", 5); + len += 7; + xpath_expr = xmlStrncatNew((xmlChar *) "/x", (xmlChar *) VARDATA(xpath_expr_text), xpath_len); + xpath_len += 2; xml_init(); PG_TRY(); { - /* redundant XML parsing (two parsings for the same value in the same session are possible) */ + /* redundant XML parsing (two parsings for the same value during one command execution are possible) */ ctxt = xmlNewParserCtxt(); if (ctxt == NULL) xml_ereport(ERROR, ERRCODE_INTERNAL_ERROR, @@ -3152,15 +3156,15 @@ if (xpathobj == NULL) ereport(ERROR, (errmsg("could not create XPath object"))); + /* + * Return empty array in cases when nothing is found + */ if (xpathobj->nodesetval == NULL) - res_is_null = TRUE; - - if (!res_is_null && xpathobj->nodesetval->nodeNr == 0) - /* TODO maybe empty array should be here, not NULL? (if so -- fix segfault) */ - /*PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, CurrentMemoryContext));*/ - res_is_null = TRUE; + res_nitems = 0; + else + res_nitems = xpathobj->nodesetval->nodeNr; - if (!res_is_null) + if (!res_is_null && res_nitems) for (i = 0; i < xpathobj->nodesetval->nodeNr; i++) { Datum elem; @@ -3196,13 +3200,11 @@ PG_END_TRY(); if (res_is_null) - { PG_RETURN_NULL(); - } + else if (res_nitems == 0) + PG_RETURN_ARRAYTYPE_P(construct_empty_array(XMLOID)); else - { PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, CurrentMemoryContext)); - } #else NO_XML_SUPPORT(); return 0; Index: src/test/regress/expected/xml_1.out =================================================================== RCS file: /projects/cvsroot/pgsql/src/test/regress/expected/xml_1.out,v retrieving revision 1.16 diff -u -r1.16 xml_1.out --- src/test/regress/expected/xml_1.out 5 Apr 2007 13:53:24 -0000 1.16 +++ src/test/regress/expected/xml_1.out 10 Apr 2007 11:51:34 -0000 @@ -326,29 +326,29 @@ (2 rows) -- Text XPath expressions evaluation -SELECT xmlpath('/value', data) FROM xmltest; - xmlpath ---------- +SELECT xpath('/value', data) FROM xmltest; + xpath +------- (0 rows) -SELECT xmlpath(NULL, NULL) IS NULL FROM xmltest; -ERROR: unsupported XML feature -DETAIL: This functionality requires libxml support. -HINT: You need to re-compile PostgreSQL using --with-libxml. -CONTEXT: SQL function "xmlpath" statement 1 -SELECT xmlpath('', ''); +SELECT xpath(NULL, NULL) IS NULL FROM xmltest; + ?column? +---------- +(0 rows) + +SELECT xpath('', ''); ERROR: unsupported XML feature DETAIL: This functionality requires libxml support. HINT: You need to re-compile PostgreSQL using --with-libxml. -SELECT xmlpath('//text()', 'number one'); +SELECT xpath('//text()', 'number one'); ERROR: unsupported XML feature DETAIL: This functionality requires libxml support. HINT: You need to re-compile PostgreSQL using --with-libxml. -SELECT xmlpath('//loc:piece/@id', 'number one', ARRAY[ARRAY['loc'], ARRAY['http://127.0.0.1']]); +SELECT xpath('//loc:piece/@id', 'number one', ARRAY[ARRAY['loc', 'http://127.0.0.1']]); ERROR: unsupported XML feature DETAIL: This functionality requires libxml support. HINT: You need to re-compile PostgreSQL using --with-libxml. -SELECT xmlpath('//b', 'one two three etc'); +SELECT xpath('//b', 'one two three etc'); ERROR: unsupported XML feature DETAIL: This functionality requires libxml support. HINT: You need to re-compile PostgreSQL using --with-libxml. Index: src/test/regress/expected/xml.out =================================================================== RCS file: /projects/cvsroot/pgsql/src/test/regress/expected/xml.out,v retrieving revision 1.17 diff -u -r1.17 xml.out --- src/test/regress/expected/xml.out 22 Mar 2007 20:26:30 -0000 1.17 +++ src/test/regress/expected/xml.out 10 Apr 2007 11:51:34 -0000 @@ -402,37 +402,37 @@ (9 rows) -- Text XPath expressions evaluation -SELECT xmlpath('/value', data) FROM xmltest; - xmlpath +SELECT xpath('/value', data) FROM xmltest; + xpath ---------------------- {one} {two} (2 rows) -SELECT xmlpath(NULL, NULL) IS NULL FROM xmltest; +SELECT xpath(NULL, NULL) IS NULL FROM xmltest; ?column? ---------- t t (2 rows) -SELECT xmlpath('', ''); +SELECT xpath('', ''); ERROR: empty XPath expression -CONTEXT: SQL function "xmlpath" statement 1 -SELECT xmlpath('//text()', 'number one'); - xmlpath +CONTEXT: SQL function "xpath" statement 1 +SELECT xpath('//text()', 'number one'); + xpath ---------------- {"number one"} (1 row) -SELECT xmlpath('//loc:piece/@id', 'number one', ARRAY[ARRAY['loc'], ARRAY['http://127.0.0.1']]); - xmlpath ---------- +SELECT xpath('//loc:piece/@id', 'number one', ARRAY[ARRAY['loc', 'http://127.0.0.1']]); + xpath +------- {1,2} (1 row) -SELECT xmlpath('//b', 'one two three etc'); - xmlpath +SELECT xpath('//b', 'one two three etc'); + xpath ------------------------- {two,etc} (1 row)