PostgreSQL 2200M Error: Causes and Solutions Complete Guide

PostgreSQL Error 2200M: invalid xml document PostgreSQL error 2200M: invalid xml document is raised when an XML value passed to XMLPARSE(DOCUMENT ...) or inserted into an xml -typed column does not conform to the W3C XML specification for a well-formed document. Unlike 2200N: invalid xml content , this error specifically targets document-level structural violations, such as missing or multiple root elements. It commonly appears during data migrations, API integrations, or when dynamically building XML strings in application code. Top 3 Causes & SQL Examples 1. Multiple or Missing Root Elements An XML document must have exactly one root element. Passing fragments or multiple top-level elements will immediately trigger this error. -- Bad: multiple root elements SELECT XMLPARSE ( DOCUMENT '<item>A</item><item>B</item>' ); -- ERROR:invalid xml document -- Bad: no root element at all SELECT XMLPARSE ( DOCUMENT 'just some text' ); -- ERROR:invalid xml document -- Good: wrap everything in a single root SELECT XMLPARSE ( DOCUMENT '<root><item>A</item><item>B</item></root>' ); 2. Unescaped Special Characters or Unclosed Tags Characters like & , < , and > must be escaped as XML entities. Unclosed tags are also a common culprit when XML is built by string concatenation. -- Bad: unescaped ampersand SELECT XMLPARSE ( DOCUMENT '<root><price>10 & 20</price></root>' ); -- ERROR:invalid xml document -- Bad: unclosed tag SELECT XMLPARSE ( DOCUMENT '<root><item>value</root>' ); -- ERROR:invalid xml document -- Good: use PostgreSQL built-in XML functions (auto-escaping) SELECT XMLELEMENT ( NAME "root" , XMLELEMENT ( NAME "price" , '10 & 20' ) ); -- Good: manually escape entities SELECT XMLPARSE ( DOCUMENT '<root><price>10 &amp; 20</price></root>' ); 3. Encoding Declaration Mismatch An <?xml version="1.0" encoding="..."> declaration that does not match the actual database encoding will cause parsing to fail. -- Check your database encoding first SHOW server_encoding ; -- e.g., UTF8 -- Bad: declared encoding differs from DB encoding SELECT XMLPARSE ( DOCUMENT '<?xml version="1.0" encoding="EUC-KR"?><root>data</root>' ); -- May raise: invalid xml document -- Good: match the declaration to your DB encoding SELECT XMLPARSE ( DOCUMENT '<?xml version="1.0" encoding="UTF-8"?><root>data</root>' ); -- Good: omit the declaration entirely SELECT XMLPARSE ( DOCUMENT '<root>data</root>' ); -- Utility function to strip problematic XML declarations CREATE OR REPLACE FUNCTION strip_xml_declaration ( p_xml TEXT ) RETURNS TEXT AS $$ BEGIN RETURN regexp_replace ( p_xml , '^ \s *< \? xml[^?]* \? > \s *' , '' , 'i' ); END ; $$ LANGUAGE plpgsql ; Quick Fix Solutions Use this validation helper before inserting any XML data: -- Safe validation wrapper CREATE OR REPLACE FUNCTION is_valid_xml ( p_text TEXT ) RETURNS BOOLEAN AS $$ BEGIN PERFORM XMLPARSE ( DOCUMENT p_text ); RETURN TRUE ; EXCEPTION WHEN invalid_xml_document THEN RETURN FALSE ; WHEN invalid_xml_content THEN RETURN FALSE ; END ; $$ LANGUAGE plpgsql ; -- Filter out bad rows before bulk insert INSERT INTO xml_store ( payload ) SELECT XMLPARSE ( DOCUMENT raw_xml ) FROM staging_table WHERE is_valid_xml ( raw_xml ); Prevention Tips Always use PostgreSQL's native XML builder functions ( XMLELEMENT , XMLFOREST , XMLAGG ) instead of string concatenation. These functions handle escaping and structure automatically, eliminating the most common sources of malformed documents. Add a CHECK constraint on XML columns and validate incoming data at the pipeline boundary before it reaches the database. -- Add constraint using the validation function ALTER TABLE xml_store ADD CONSTRAINT chk_valid_xml_doc CHECK ( is_valid_xml ( payload :: text )); -- Prefer the native xml type over text for automatic parse-time validation CREATE TABLE documents ( id SERIAL PRIMARY KEY , content XML NOT NULL -- PostgreSQL validates on insert automatically ); Related Errors Code Name Notes 2200N invalid xml content Triggered by XMLPARSE(CONTENT ...) with structural issues 22000 data exception Parent category for all data-related exceptions 42804 datatype mismatch Occurs when a non-XML value is cast to the xml type incorrectly 📖 Want a more detailed guide? Check out the full in-depth version (Korean) on oraerror.com — includes detailed analysis, additional SQL examples, and prevention tips.