Various fixes in the logic of XML functions:

- Add new SQL command SET XML OPTION (also available via regular GUC) to
  control the DOCUMENT vs. CONTENT option in implicit parsing and
  serialization operations.

- Subtle corrections in the handling of the standalone property in
  xmlroot().

- Allow xmlroot() to work on content fragments.

- Subtle corrections in the handling of the version property in
  xmlconcat().

- Code refactoring for producing XML declarations.

2 files changed, 52 insertions, 2 deletions

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 94fc8fd79aa..2a95d8fae73 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.105 2007/01/25 04:35:10 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.106 2007/01/25 11:53:50 petere Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -3558,6 +3558,38 @@ SELECT * FROM parent WHERE key = 2400;
       </listitem>
      </varlistentry>
      
+     <varlistentry id="guc-xmloption" xreflabel="xmloption">
+      <term><varname>xmloption</varname> (<type>string</type>)</term>
+      <indexterm>
+       <primary><varname>xmloption</> configuration parameter</primary>
+      </indexterm>
+      <indexterm>
+       <primary><varname>SET XML OPTION</></primary>
+      </indexterm>
+      <indexterm>
+       <primary><varname>XML option</></primary>
+      </indexterm>
+      <listitem>
+       <para>
+        Sets whether <literal>DOCUMENT</literal> or
+        <literal>CONTENT</literal> is implicit when converting between
+        XML and character string values.  See <xref
+        linkend="datatype-xml"> for a description of this.  Valid
+        values are <literal>DOCUMENT</literal> and
+        <literal>CONTENT</literal>.  The default is
+        <literal>CONTENT</literal>.
+       </para>
+
+       <para>
+        According to the SQL standard, the command to set this option is
+<synopsis>
+SET XML OPTION { DOCUMENT | CONTENT };
+</synopsis>
+        This syntax is also available in PostgreSQL.
+       </para>
+      </listitem>
+     </varlistentry>
+     
      </variablelist>
     </sect2>
      <sect2 id="runtime-config-client-format">
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index 47c2e5c74af..f0ba6c32c71 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.185 2007/01/18 13:59:11 petere Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.186 2007/01/25 11:53:50 petere Exp $ -->
 
  <chapter id="datatype">
   <title id="datatype-title">Data Types</title>
@@ -3475,6 +3475,24 @@ XMLSERIALIZE ( { DOCUMENT | CONTENT } <replaceable>value</replaceable> AS <repla
    </para>
 
    <para>
+    When character string values are cast to or from type
+    <type>xml</type> without going through <type>XMLPARSE</type> or
+    <type>XMLSERIALIZE</type>, respectively, the choice of
+    <literal>DOCUMENT</literal> versus <literal>CONTENT</literal> is
+    determined by the <quote>XML option</quote> session configuration
+    parameter, which can be set using the standard command
+<synopsis>
+SET XML OPTION { DOCUMENT | CONTENT };
+</synopsis>
+    or the more PostgreSQL-like syntax
+<synopsis>
+SET xmloption TO { DOCUMENT | CONTENT };
+</synopsis>
+    The default is <literal>CONTENT</literal>, so all forms of XML
+    data are allowed.
+   </para>
+
+   <para>
     Care must be taken when dealing with multiple character encodings
     on the client, server, and in the XML data passed through them.
     When using the text mode to pass queries to the server and query