diff options
| -rw-r--r-- | doc/src/sgml/func.sgml | 39 | ||||
| -rw-r--r-- | src/backend/catalog/sql_features.txt | 4 | ||||
| -rw-r--r-- | src/backend/parser/gram.y | 15 |
3 files changed, 37 insertions, 21 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 6765b0d584c..774d5b3fce1 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -10583,7 +10583,7 @@ SELECT xmlagg(x) FROM (SELECT * FROM test ORDER BY y DESC) AS tab; </indexterm> <synopsis> -<function>XMLEXISTS</function>(<replaceable>text</replaceable> PASSING <optional>BY REF</optional> <replaceable>xml</replaceable> <optional>BY REF</optional>) +<function>XMLEXISTS</function>(<replaceable>text</replaceable> PASSING <optional>BY { REF | VALUE }</optional> <replaceable>xml</replaceable> <optional>BY { REF | VALUE }</optional>) </synopsis> <para> @@ -10596,7 +10596,7 @@ SELECT xmlagg(x) FROM (SELECT * FROM test ORDER BY y DESC) AS tab; <para> Example: <screen><![CDATA[ -SELECT xmlexists('//town[text() = ''Toronto'']' PASSING BY REF '<towns><town>Toronto</town><town>Ottawa</town></towns>'); +SELECT xmlexists('//town[text() = ''Toronto'']' PASSING BY VALUE '<towns><town>Toronto</town><town>Ottawa</town></towns>'); xmlexists ------------ @@ -10606,14 +10606,25 @@ SELECT xmlexists('//town[text() = ''Toronto'']' PASSING BY REF '<towns><town>Tor </para> <para> - The <literal>BY REF</literal> clauses have no effect in - PostgreSQL, but are allowed for SQL conformance and compatibility - with other implementations. Per SQL standard, the - first <literal>BY REF</literal> is required, the second is - optional. Also note that the SQL standard specifies - the <function>xmlexists</function> construct to take an XQuery - expression as first argument, but PostgreSQL currently only - supports XPath, which is a subset of XQuery. + The <literal>BY REF</literal> or <literal>BY VALUE</literal> clauses + have no effect in <productname>PostgreSQL<productname>, but are allowed + for compatibility with other implementations. Per the <acronym>SQL</acronym> + standard, the one that precedes any argument is required, and indicates + the default for arguments that follow, and one may follow any argument to + override the default. + <productname>PostgreSQL</productname> ignores <literal>BY REF</literal> + and passes by value always. + </para> + + <para> + In the <acronym>SQL</acronym> standard, an <function>xmlexists</function> + construct evaluates an expression in the XQuery language, allows passing + values for named parameters in the expression as well as for the context + item, and does not require the passed values to be documents, or even of + XML type. + In <productname>PostgreSQL</productname>, this construct currently only + evaluates an XPath 1.0 expression, and allows passing only one value, + which must be an XML document, to be the context item. </para> </sect3> @@ -10820,7 +10831,7 @@ SELECT xpath_exists('/my:a/text()', '<my:a xmlns:my="http://example.com">test</m <synopsis> <function>xmltable</function>( <optional>XMLNAMESPACES(<replaceable>namespace uri</replaceable> AS <replaceable>namespace name</replaceable><optional>, ...</optional>), </optional> - <replaceable>row_expression</replaceable> PASSING <optional>BY REF</optional> <replaceable>document_expression</replaceable> <optional>BY REF</optional> + <replaceable>row_expression</replaceable> PASSING <optional>BY { REF | VALUE }</optional> <replaceable>document_expression</replaceable> <optional>BY { REF | VALUE }</optional> COLUMNS <replaceable>name</replaceable> { <replaceable>type</replaceable> <optional>PATH <replaceable>column_expression</replaceable></optional> <optional>DEFAULT <replaceable>default_expression</replaceable></optional> <optional>NOT NULL | NULL</optional> | FOR ORDINALITY } <optional>, ...</optional> @@ -10850,11 +10861,11 @@ SELECT xpath_exists('/my:a/text()', '<my:a xmlns:my="http://example.com">test</m <para> <replaceable>document_expression</replaceable> provides the XML document to operate on. - The <literal>BY REF</literal> clauses have no effect in PostgreSQL, - but are allowed for SQL conformance and compatibility with other - implementations. The argument must be a well-formed XML document; fragments/forests are not accepted. + The <literal>BY REF</literal> or <literal>BY VALUE</literal> clauses are + accepted, as described for the <function>xmlexists</function> predicate, + but ignored; PostgreSQL currently passes XML by value always. </para> <para> diff --git a/src/backend/catalog/sql_features.txt b/src/backend/catalog/sql_features.txt index aeb262a5b0e..bade0fe9aeb 100644 --- a/src/backend/catalog/sql_features.txt +++ b/src/backend/catalog/sql_features.txt @@ -635,8 +635,8 @@ X204 XMLQuery: initializing an XQuery variable NO X205 XMLQuery: EMPTY ON EMPTY option NO X206 XMLQuery: NULL ON EMPTY option NO X211 XML 1.1 support NO -X221 XML passing mechanism BY VALUE NO -X222 XML passing mechanism BY REF YES +X221 XML passing mechanism BY VALUE YES +X222 XML passing mechanism BY REF NO parser accepts BY REF but ignores it; passing is always BY VALUE X231 XML(CONTENT(UNTYPED)) type NO X232 XML(CONTENT(ANY)) type NO X241 RETURNING CONTENT in XML publishing NO diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 753af6073f3..e23e68fdb33 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -13951,20 +13951,25 @@ xmlexists_argument: { $$ = $2; } - | PASSING c_expr BY REF + | PASSING c_expr xml_passing_mech { $$ = $2; } - | PASSING BY REF c_expr + | PASSING xml_passing_mech c_expr { - $$ = $4; + $$ = $3; } - | PASSING BY REF c_expr BY REF + | PASSING xml_passing_mech c_expr xml_passing_mech { - $$ = $4; + $$ = $3; } ; +xml_passing_mech: + BY REF + | BY VALUE_P + ; + /* * Aggregate decoration clauses |