XML Database and Oracle Solution for XML
Introduction
Since XML emerged as the future substitution of HTML on the Internet document,
database companies have also tried to support XML document on their DBMS. Many
traditional relational database based companies have been developing the interface
between relational tables and some companies have been focused on the native XML
database system instead of table-based storages.
This survey started to find out promising native XML database systems that are relatively
cheap and reliable with useful interface with World Wide Web. However, it is not easy to
find the database that comes to our requirements though there are many XML databases
available through the Internet. Some of them seem rather a file system than a database.
Current database dominating Oracle Company suggest its solution for XML document.
XML database
XML database is a database that can manipulate an XML document within database and
provide DBMS functions. However, the data format for the XML could be saved any
form. XML document can be saved as an entire text form – BLOB in RDB or a file,
modified form like a parsed binary form, and mapping XML document structure to the
database. Some traditional relational database companies provide utilities that enable
XML converting to/from relational tables. In the viewpoint of the users, the structure of
the internal database is not important. They only want the fast and convenient processes
of XML and actual HTML pages.
The table below shows list of some XML databases/repositories that process XML
documents directly.
Name
O/S
Description
XDBM
Linux
XDBM seems like a C library which supports database
Win32(DLL)
functions. It saves each XML files to an XDBM file and
manages only one XML at a time. That means it cannot do
any combined access on multiple XML documents at any
time. It would be only useful on a single long XML
document which has many elements.
TEXTML
WinNT
This Server is a back-end XML document server whose
purpose is to store index and retrieve XML content. The
TEXTML Server is a powerful document centric alternative
to relational and object oriented databases, with unmatched
performances on large volumes of XML content. TEXTML
Server parses XML documents to build indices of values
according to the index rules defined by the database
administrator, thus eliminating the overhead associated
with indexing XML content. It seems powerful XML server,
but depends on Microsoft architecture. It produces through
ASP.
Lore
Solaris
Linux
Lore is a declarative query language for XML, developing
new technology for interactive searches over XML data,
and building an efficient XML query processor.
Ozone
(Java base)
Ozone is based on open source, Java based, objectoriented database. Ozone's implementation through DOM
implementation. Apache is also supported by classes,
Xerces-J and Xalan-J. Ozone does not depend on any
back-end database or mapping technology to actually save
objects. It contains its own clustered storage and cache
system to handle persistent Java objects. It’s a kind of Java
tool to process XML document. It does not seem reliable.
RDFDB
Linux
(C source, Perl)
RDFDB is intended to be a simple, scalable, open-source
database for RDF. (RDF: The Resource Description
Framework integrates a variety of web-based metadata
activities using XML as an interchange syntax.)
XML-DBMS
(Java and Perl)
XML-DBMS is middleware for transferring data between
XML documents and relational databases.
Birdstep
Win32
WinCE
Epoc
Palm/OS
VxWorks
Linux
This seems promising as it supports all possible machines'
operating system. Only kernels for Win32, WinCE, and
Linux are available now. Birdstep will cooperate with
Tamino for hand-held platform.
However, it only provides primitive user interface and basic
functions currently.
Please see Kanseok’s page and presentation on detail.
dbXML
Linux
Unix
Win32
“dbXML” core version is GNU.
Tamino
Tamino is the promising native XML Information Server. It supports not only pure XML
documents but also any type of application document and traditional relational
information.
Tamino provides an engine (X-Machine), Internet interface (X-Port), SQL engine, a data
map, a module (X-Node) for interfacing to external data access, and a development kit.
The structure of the engine can be described as below figure.
As Tamino includes Web server, the objects of Tamino can be accessed directly through
URL.
The native XML database makes itself more convenient to updating XML structure and
locking the unit of XML than multiple tables in relational database.
However, Tamino is relatively expensive ($25,000) and its usage is not as frequently as
other relational databases like DB2 and Oracle.
Oracle
Oracle is a typical traditional relational database company. As XML is emerging as a
next generation document format, Oracle also provides several kinds of XML supports.
One effort for the XML is the mapping to the XML elements to the relational tables. As
the elements of XML could be thought as attributes of the table, converting XML to
database tables or extracting XML elements from tables are possible through PL/SQL
procedure or any other utilities. Oracle produce Jdeveloper as an integrated interface to
Java with CORBA, EJB, and Java Stored Procedures leveraging Oracle's XML/XSLT
components to build powerful multi-tier applications. XSU (XML-SQL Utility) is a
server side Java embedded tool to transform XML document and database attributes.
Though it has some bugs, it works fine for the simple XML document converting.
However, those transformations are not good to the complicated XML documents that
include several attributes (not columns in tables) and need to be divided into several
tables. Updating XML structure may cause large amount coding in such procedures.
LOB (Large OBjects) with Oracle intermedia XML search is another solution for XML
document and it is a native XML database form. The size of document is allowed up to 4
gigabytes and searching with indexing is powerful. This model would be fit to large
single complicated XML document files.
New Oracle 9i includes native XML Support (XDB), which introduces new SQL type,
XML Type, and it is even accessible through HTTP and JMS (Java Messaging Service).