v2-0001-Accept-TEXT-and-CDATA-nodes-in-XMLTABLE-s-column_exp.patch

text/plain

Filename: v2-0001-Accept-TEXT-and-CDATA-nodes-in-XMLTABLE-s-column_exp.patch
Type: text/plain
Part: 0
Message: Re: XML/XPath issues: text/CDATA in XMLTABLE, XPath evaluated with wrong context

Patch

Format: unified
Series: patch v2-0001
File+
src/backend/utils/adt/xml.c 15 17
src/test/regress/expected/xml_2.out 6 6
src/test/regress/expected/xml.out 6 6
src/test/regress/sql/xml.sql 2 2
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 233dd63e89..06bdbaf7c9 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -4505,11 +4505,22 @@ XmlTableGetValue(TableFuncScanState *state, int colnum,
 			else if (count == 1)
 			{
 				xmlChar    *str;
+				xmlNodePtr	object;
 
-				str = xmlNodeListGetString(xtCxt->doc,
-										   xpathobj->nodesetval->nodeTab[0]->xmlChildrenNode,
-										   1);
+				object = xpathobj->nodesetval->nodeTab[0];
 
+				/*
+				 * Most nodes (elements and even attributes) store their data
+				 * in child nodes.  If they don't have child nodes, it means
+				 * that they are empty (e.g. <element/>).  Text nodes and
+				 * CDATA sections are the exception: they don't have children
+				 * but the contents are in the Text/CDATA node itself.
+				 */
+				if (object->type != XML_CDATA_SECTION_NODE &&
+					object->type != XML_TEXT_NODE)
+					object = object->children;
+
+				str = xmlNodeListGetString(xtCxt->doc, object, 1);
 				if (str != NULL)
 				{
 					PG_TRY();
@@ -4528,10 +4539,7 @@ XmlTableGetValue(TableFuncScanState *state, int colnum,
 				{
 					/*
 					 * This line ensure mapping of empty tags to PostgreSQL
-					 * value. Usually we would to map a empty tag to empty
-					 * string. But this mapping can create empty string when
-					 * user doesn't expect it - when empty tag is enforced by
-					 * libxml2 - when user uses a text() function for example.
+					 * values.
 					 */
 					cstr = "";
 				}
@@ -4543,16 +4551,6 @@ XmlTableGetValue(TableFuncScanState *state, int colnum,
 
 				Assert(count > 1);
 
-				/*
-				 * When evaluating the XPath expression returns multiple
-				 * nodes, the result is the concatenation of them all. The
-				 * target type must be XML.
-				 */
-				if (typid != XMLOID)
-					ereport(ERROR,
-							(errcode(ERRCODE_CARDINALITY_VIOLATION),
-							 errmsg("more than one value returned by column XPath expression")));
-
 				/* Concatenate serialized values */
 				initStringInfo(&str);
 				for (i = 0; i < count; i++)
diff --git a/src/test/regress/expected/xml.out b/src/test/regress/expected/xml.out
index 7fa1309108..3eb638ca25 100644
--- a/src/test/regress/expected/xml.out
+++ b/src/test/regress/expected/xml.out
@@ -1024,7 +1024,7 @@ SELECT  xmltable.*
                          PASSING data
                          COLUMNS id int PATH '@id',
                                   _id FOR ORDINALITY,
-                                  country_name text PATH 'COUNTRY_NAME' NOT NULL,
+                                  country_name text PATH 'COUNTRY_NAME/text()' NOT NULL,
                                   country_id text PATH 'COUNTRY_ID',
                                   region_id int PATH 'REGION_ID',
                                   size float PATH 'SIZE',
@@ -1046,7 +1046,7 @@ CREATE VIEW xmltableview1 AS SELECT  xmltable.*
                          PASSING data
                          COLUMNS id int PATH '@id',
                                   _id FOR ORDINALITY,
-                                  country_name text PATH 'COUNTRY_NAME' NOT NULL,
+                                  country_name text PATH 'COUNTRY_NAME/text()' NOT NULL,
                                   country_id text PATH 'COUNTRY_ID',
                                   region_id int PATH 'REGION_ID',
                                   size float PATH 'SIZE',
@@ -1075,7 +1075,7 @@ CREATE OR REPLACE VIEW public.xmltableview1 AS
     "xmltable".premier_name
    FROM ( SELECT xmldata.data
            FROM xmldata) x,
-    LATERAL XMLTABLE(('/ROWS/ROW'::text) PASSING (x.data) COLUMNS id integer PATH ('@id'::text), _id FOR ORDINALITY, country_name text PATH ('COUNTRY_NAME'::text) NOT NULL, country_id text PATH ('COUNTRY_ID'::text), region_id integer PATH ('REGION_ID'::text), size double precision PATH ('SIZE'::text), unit text PATH ('SIZE/@unit'::text), premier_name text DEFAULT ('not specified'::text) PATH ('PREMIER_NAME'::text))
+    LATERAL XMLTABLE(('/ROWS/ROW'::text) PASSING (x.data) COLUMNS id integer PATH ('@id'::text), _id FOR ORDINALITY, country_name text PATH ('COUNTRY_NAME/text()'::text) NOT NULL, country_id text PATH ('COUNTRY_ID'::text), region_id integer PATH ('REGION_ID'::text), size double precision PATH ('SIZE'::text), unit text PATH ('SIZE/@unit'::text), premier_name text DEFAULT ('not specified'::text) PATH ('PREMIER_NAME'::text))
 EXPLAIN (COSTS OFF) SELECT * FROM xmltableview1;
                QUERY PLAN                
 -----------------------------------------
@@ -1085,15 +1085,15 @@ EXPLAIN (COSTS OFF) SELECT * FROM xmltableview1;
 (3 rows)
 
 EXPLAIN (COSTS OFF, VERBOSE) SELECT * FROM xmltableview1;
-                                                                                                                                                                                                                        QUERY PLAN                                                                                                                                                                                                                         
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                                            QUERY PLAN                                                                                                                                                                                                                            
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Nested Loop
    Output: "xmltable".id, "xmltable"._id, "xmltable".country_name, "xmltable".country_id, "xmltable".region_id, "xmltable".size, "xmltable".unit, "xmltable".premier_name
    ->  Seq Scan on public.xmldata
          Output: xmldata.data
    ->  Table Function Scan on "xmltable"
          Output: "xmltable".id, "xmltable"._id, "xmltable".country_name, "xmltable".country_id, "xmltable".region_id, "xmltable".size, "xmltable".unit, "xmltable".premier_name
-         Table Function Call: XMLTABLE(('/ROWS/ROW'::text) PASSING (xmldata.data) COLUMNS id integer PATH ('@id'::text), _id FOR ORDINALITY, country_name text PATH ('COUNTRY_NAME'::text) NOT NULL, country_id text PATH ('COUNTRY_ID'::text), region_id integer PATH ('REGION_ID'::text), size double precision PATH ('SIZE'::text), unit text PATH ('SIZE/@unit'::text), premier_name text DEFAULT ('not specified'::text) PATH ('PREMIER_NAME'::text))
+         Table Function Call: XMLTABLE(('/ROWS/ROW'::text) PASSING (xmldata.data) COLUMNS id integer PATH ('@id'::text), _id FOR ORDINALITY, country_name text PATH ('COUNTRY_NAME/text()'::text) NOT NULL, country_id text PATH ('COUNTRY_ID'::text), region_id integer PATH ('REGION_ID'::text), size double precision PATH ('SIZE'::text), unit text PATH ('SIZE/@unit'::text), premier_name text DEFAULT ('not specified'::text) PATH ('PREMIER_NAME'::text))
 (7 rows)
 
 -- XMLNAMESPACES tests
diff --git a/src/test/regress/expected/xml_2.out b/src/test/regress/expected/xml_2.out
index 112ebe47cd..cb865a9ef7 100644
--- a/src/test/regress/expected/xml_2.out
+++ b/src/test/regress/expected/xml_2.out
@@ -1004,7 +1004,7 @@ SELECT  xmltable.*
                          PASSING data
                          COLUMNS id int PATH '@id',
                                   _id FOR ORDINALITY,
-                                  country_name text PATH 'COUNTRY_NAME' NOT NULL,
+                                  country_name text PATH 'COUNTRY_NAME/text()' NOT NULL,
                                   country_id text PATH 'COUNTRY_ID',
                                   region_id int PATH 'REGION_ID',
                                   size float PATH 'SIZE',
@@ -1026,7 +1026,7 @@ CREATE VIEW xmltableview1 AS SELECT  xmltable.*
                          PASSING data
                          COLUMNS id int PATH '@id',
                                   _id FOR ORDINALITY,
-                                  country_name text PATH 'COUNTRY_NAME' NOT NULL,
+                                  country_name text PATH 'COUNTRY_NAME/text()' NOT NULL,
                                   country_id text PATH 'COUNTRY_ID',
                                   region_id int PATH 'REGION_ID',
                                   size float PATH 'SIZE',
@@ -1055,7 +1055,7 @@ CREATE OR REPLACE VIEW public.xmltableview1 AS
     "xmltable".premier_name
    FROM ( SELECT xmldata.data
            FROM xmldata) x,
-    LATERAL XMLTABLE(('/ROWS/ROW'::text) PASSING (x.data) COLUMNS id integer PATH ('@id'::text), _id FOR ORDINALITY, country_name text PATH ('COUNTRY_NAME'::text) NOT NULL, country_id text PATH ('COUNTRY_ID'::text), region_id integer PATH ('REGION_ID'::text), size double precision PATH ('SIZE'::text), unit text PATH ('SIZE/@unit'::text), premier_name text DEFAULT ('not specified'::text) PATH ('PREMIER_NAME'::text))
+    LATERAL XMLTABLE(('/ROWS/ROW'::text) PASSING (x.data) COLUMNS id integer PATH ('@id'::text), _id FOR ORDINALITY, country_name text PATH ('COUNTRY_NAME/text()'::text) NOT NULL, country_id text PATH ('COUNTRY_ID'::text), region_id integer PATH ('REGION_ID'::text), size double precision PATH ('SIZE'::text), unit text PATH ('SIZE/@unit'::text), premier_name text DEFAULT ('not specified'::text) PATH ('PREMIER_NAME'::text))
 EXPLAIN (COSTS OFF) SELECT * FROM xmltableview1;
                QUERY PLAN                
 -----------------------------------------
@@ -1065,15 +1065,15 @@ EXPLAIN (COSTS OFF) SELECT * FROM xmltableview1;
 (3 rows)
 
 EXPLAIN (COSTS OFF, VERBOSE) SELECT * FROM xmltableview1;
-                                                                                                                                                                                                                        QUERY PLAN                                                                                                                                                                                                                         
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+                                                                                                                                                                                                                            QUERY PLAN                                                                                                                                                                                                                            
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Nested Loop
    Output: "xmltable".id, "xmltable"._id, "xmltable".country_name, "xmltable".country_id, "xmltable".region_id, "xmltable".size, "xmltable".unit, "xmltable".premier_name
    ->  Seq Scan on public.xmldata
          Output: xmldata.data
    ->  Table Function Scan on "xmltable"
          Output: "xmltable".id, "xmltable"._id, "xmltable".country_name, "xmltable".country_id, "xmltable".region_id, "xmltable".size, "xmltable".unit, "xmltable".premier_name
-         Table Function Call: XMLTABLE(('/ROWS/ROW'::text) PASSING (xmldata.data) COLUMNS id integer PATH ('@id'::text), _id FOR ORDINALITY, country_name text PATH ('COUNTRY_NAME'::text) NOT NULL, country_id text PATH ('COUNTRY_ID'::text), region_id integer PATH ('REGION_ID'::text), size double precision PATH ('SIZE'::text), unit text PATH ('SIZE/@unit'::text), premier_name text DEFAULT ('not specified'::text) PATH ('PREMIER_NAME'::text))
+         Table Function Call: XMLTABLE(('/ROWS/ROW'::text) PASSING (xmldata.data) COLUMNS id integer PATH ('@id'::text), _id FOR ORDINALITY, country_name text PATH ('COUNTRY_NAME/text()'::text) NOT NULL, country_id text PATH ('COUNTRY_ID'::text), region_id integer PATH ('REGION_ID'::text), size double precision PATH ('SIZE'::text), unit text PATH ('SIZE/@unit'::text), premier_name text DEFAULT ('not specified'::text) PATH ('PREMIER_NAME'::text))
 (7 rows)
 
 -- XMLNAMESPACES tests
diff --git a/src/test/regress/sql/xml.sql b/src/test/regress/sql/xml.sql
index cb96e18005..c223603a1f 100644
--- a/src/test/regress/sql/xml.sql
+++ b/src/test/regress/sql/xml.sql
@@ -349,7 +349,7 @@ SELECT  xmltable.*
                          PASSING data
                          COLUMNS id int PATH '@id',
                                   _id FOR ORDINALITY,
-                                  country_name text PATH 'COUNTRY_NAME' NOT NULL,
+                                  country_name text PATH 'COUNTRY_NAME/text()' NOT NULL,
                                   country_id text PATH 'COUNTRY_ID',
                                   region_id int PATH 'REGION_ID',
                                   size float PATH 'SIZE',
@@ -362,7 +362,7 @@ CREATE VIEW xmltableview1 AS SELECT  xmltable.*
                          PASSING data
                          COLUMNS id int PATH '@id',
                                   _id FOR ORDINALITY,
-                                  country_name text PATH 'COUNTRY_NAME' NOT NULL,
+                                  country_name text PATH 'COUNTRY_NAME/text()' NOT NULL,
                                   country_id text PATH 'COUNTRY_ID',
                                   region_id int PATH 'REGION_ID',
                                   size float PATH 'SIZE',