XML for Analysis (XMLA) is an industry standard for data access in analytical systems, such as

online analytical processing Online analytical processing, or OLAP (), is an approach to answer multi-dimensional analytical (MDA) queries swiftly in computing. OLAP is part of the broader category of business intelligence, which also encompasses relational databases, repor ...

(OLAP) and data mining. XMLA is based on other industry standards such as

XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...

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and

HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...

. XMLA is maintained by XMLA Council with

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...

, Hyperion and

SAS Institute SAS Institute (or SAS, pronounced "sass") is an American multinational developer of analytics software based in Cary, North Carolina. SAS develops and markets a suite of analytics software ( also called SAS), which helps access, manage, ana ...

being the XMLA Council founder members.

History

The XMLA specification was first proposed by

as a successor for OLE DB for OLAP in April 2000. By January 2001 it was joined by Hyperion endorsing XMLA. The 1.0 version of the standard was released in April 2001, and in September 2001 the XMLA Council was formed. In April 2002 SAS joined Microsoft and Hyperion as founding member of XMLA Council. With time, more than 25 companies joined with their support for the standard.

API

XMLA consists of only two

methods.: execute and discover. It was designed in such a way to preserve simplicity.

Execute

Execute method has two parameters: * Command - command to be executed. It can be MDX,

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or SQL. * Properties -

list of command properties such as Timeout, Catalog name, etc. The result of Execute command could be ''Multidimensional Dataset'' or ''Tabular Rowset''.

Discover

Discover method was designed to model all the discovery methods possible in

OLEDB OLE DB (''Object Linking and Embedding, Database'', sometimes written as OLEDB or OLE-DB), an API designed by Microsoft, allows accessing data from a variety of sources in a uniform manner. The API provides a set of interfaces implemented using ...

including various schema rowset, properties, keywords, etc. Discover method allows users to specify both what needs to be discovered and the possible restrictions or properties. The result of Discover method is a rowset.

Query language

XMLA specifies MDXML as the query language. In the XMLA 1.1 version, the only construct in MDXML is an MDX statement enclosed in the tag.

Example

Below is an example of XMLA Execute request with MDX query in command. SELECT Measures.MEMBERS ON COLUMNS FROM Sales FoodMart Multidimensional TupleFormat

Session management

XMLA has a notion of ''session state''. It is maintained through predefined ''

headers'' * BeginSession - to begin a new session * EndSession - to end existing session * UseSession - to use existing session. SessionId attribute previously returned for BeginSession should be used.

References

External links

XMLA resources and links
{{Data warehouse XML-based standards Online analytical processing Application programming interfaces