Binary XML Storage

October 16

Just to start off the 11gR2 series, here the first small “HOWTO” post regarding the new features in Oracle 11gR2. The 11gR2 database supports now 3 binary XML partitioning options. Partitioning has great advantages, if you are dealing with huge volumes of XML data. Those advantages are mainly regarding maintenance, for instance updating/refreshing data, or the local partitioning index that belongs to the specific partition that you want to alter. You can use this form of partitioning on XMLType Columns and XMLType Tables, XML Schema based or Schema-less.

Binary XML XMLType should be used, most of the time, if you are dealing with content/data driven environments (XML Schema based) or document driven (if XML Schema less). The following 3 options are now available:

  1. range
  2. list
  3. hash

XML Partitioning is based on a column or a virtual column and is defined via the XMLTABLE function/syntax. You are allowed to pass on a XML resultset/fragment into the next nested XMLTABLE syntax, but only once. See the Oracle XMLDB Developers Guides for more information.
Read MoreHOWTO: Partition Binary XML, XMLType Storage

June 17

I wondered, for a long time, if it were possible to shred automatically XML documents, via Binary XML XMLType storage, the same way as you are able with Object Relational XMLType storage since the Oracle version (the first officially supported XMLDB database version).

Based on “standard” object relational storage you need the following requirements and/or take the following steps:

  • Annotate an XML Schema with the XDB namespace and xdb:annotations to your liking
  • Register this XML Schema in the XDB Repository
  • During registration automatically generate the needed types and tables (based on your xdb:annotations)
  • An XML document(s) that validates properly, is valid, against your registered XML Schema.

If done properly, drag & dropping your XML documents via for example WebDAV via the enable protocol server, will cause the XDB functionality to check and validate the given XML documents against the registered XML Schema and insert the content automatically in the generated table(s). This mechanism also works via the FTP protocol functionality off the XDB Protocol Server.

I never got it really to work, at least the mechanism was fuzzy to me. Sometimes it did work as expected, sometimes it didn’t. What I didn’t realize, is that I most of the time use XML documents with multiple namespace references. Until one of my students during an XMLDB training, hit a small bug (8473369), regarding using duplicate namespaces in the “wrong” order. XQuery statement don’t have the problem, XML/SQL does, so I reported it via an Service Request. This made me wonder… Would I have the same issue with the namespace references in the registered XML Schema and the XML document. I still have to check the W3C Official XML Namespace Recommendation regarding this issue though…

Read MoreHOWTO: Shred Binary XML Documents Directly into a Default Database Table

September 5

This post will show you some of the first numbers I collected regarding “Loading XML data”, while making use of different XMLType “physical storage containers”.

I also have done some initial testing with Object Relational XMLType storage, but because this method of storage has many options and extra features, I won’t describe them yet here. This topic is interesting enough to earn its on post.

If you need some background on Oracle XMLType Storage option than have a read through the “Binary-, CLOB, Object Relational Storage” Category option in the menu, the Oracle XMLDB Developers Manual or a short intro via Oracle 11g – XMLType Storage Options.

After having created an environment as described in “XMLDB Performance: Environment, Set-up, Procedure“, the following results were gathered by me while keeping values constant, for example the values for “connection.xml“, as described in the “XMLDB Performance: Environment, Set-up, Procedure” . Only the WIKI_STAGE create statements are different.

Read MoreXMLDB Performance: Binary XML Storage Models