Use external DTD in 11g

Question

Hi,
I try to parse an XML file within a CLOB column. In Oracle 9i and 10g the code work, but in 11 I get a lot of errors.
First I got
ORA-31020: Der Vorgang ist nicht zulässig, Ursache: For security reasons, ftp and http access over XDB repository is not allowed on server side (-31020)
The XML file contains a reference to an external DTD, which is accessible per HTTP on a remote webserver.
As I have understood, I have to register all my DTDs within the Oracle Database. I found
dbms_xmlschema.registerURI()
to do the job. This is very unpractical, because there are a lot of DTDs, which can be referenced by the XML-CLOBs. So I have to register all the DTDs manually.
Normally the XML generator adds the matching DTD reference and so I can validate the XML with the parser without any knowledge about the type of the DTD.
To figure out the problem I read a lot of documents on severyl websites. I have tried
select HTTPURITYPE('http://mywebserver.domain/schema/mydtd-v1.0.dtd').getCLob() from dual;
to load the DTD content. Surprise, surprise I got a lot of ACL errors. To solve that, I have added some network acls. At the moment the statement above
returns my DTD within a CLOB now, so it seems, that I can load the external file from the remote webserver.
Back to registerURI():
dbms_xmlschema.registerURI(
      schemaURL => 'http://mywebserver.domain/schema/mydtd-v1.0.dtd',
      schemaDocUri => 'http://mywebserver.domain/schema/mydtd-v1.0.dtd',
      local => false);
returns now (error messages in German)
ORA-31011: XML-Parsing nicht erfolgreich
ORA-19202: Fehler bei XML-Verarbeitung
LPX-00247: Ungültige Dokument-Typ-Deklaration (DTD)
Error at line 5
aufgetreten
ORA-06512: in "XDB.DBMS_XMLSCHEMA_INT", Zeile 20
ORA-06512: in "XDB.DBMS_XMLSCHEMA", Zeile 199
ORA-06512: in Zeile 12
The same error occurs on
dbms_xmlschema.registerschema(
      schemaURL => 'http://mywebserver.domain/schema/mydtd-v1.0.dtd',
      schemaDoc => HTTPURITYPE('http://mywebserver.domain/schema/mydtd-v1.0.dtd').getCLob()
How I can get more information about the underlying error? I have tried to enable tracing for some XDB events, but in the udump directory
exist only old files. I think, the DTD is correct, also the reference within the XML CLOB (because it works on the old database instances).
It seems to be a security or character-set(?) issue.
Any ideas?
Thanks a lot
Andre

Answer 1

As I have understood, I have to register all my DTDs within the Oracle Database.
Not exactly.
DBMS_XMLSchema procedures deal with XML schemas, not DTDs.
You can have Oracle resolve the DTD by loading it into the XML DB repository at the same uri referenced by the XML file.
Or, if you don't actually need to use those DTDs to validate XML documents, you can also disable DTD validation altogether at session or instance level.