Databases Reference
In-Depth Information
CHAPTER
32
IN THIS CHAPTER
.
State Management
XML for Analysis
.
XML/A Methods
.
Handling Errors and Warnings
X
ML for Analysis (XML/A) is a standard protocol for
access to multidimensional data. It enables any client appli-
cations access to any multidimensional database that
supports XML/A.
XML/A was designed as a web-based data access standard. It
was intended to serve as “glue” between applications and
distributed multidimensional data sources over the web and
enterprise networks. In Analysis Services 2005, the role of
XML/A was extended from web access to that of a standard
protocol enabling data access to Analysis Services. (You can
find the XML/A specification at
http://www.xmla.org.)
XML/A derives much of its underlying foundation from the
OLE DB standard. For example, all the schema rowsets
defined by OLE DB and the OLE DB for OLAP specification
are supported by XML/A. The properties are similar, but in
the transition from OLE DB to XML/A, significant changes
had to be made to fit into a web-based, stateless world.
XML/A defines a standard XML format for messages and
the representation of multidimensional data types. It uses
XML and Simple Object Access Protocol (SOAP) to generate
messages and process the results. SOAP, originally based on
Hypertext Transfer Protocol (HTTP), defines a format based
on XML for the exchange of messages between applica-
tions. It replaces such protocols as Remote Procedure Call
(RPC), Common Object Request Broker Architecture
(CORBA), and Distributed Component Object Model
(DCOM), which are not suitable for the exchange of infor-
mation via the Internet. Version 1.1 of SOAP can use other
transport protocols, such as Transport Control Protocol
(TCP). SOAP defines the format of requests, whereas XML/A
defines the messages needed for access to data.
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