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

online analytical processing In computing, online analytical processing (OLAP) (), is an approach to quickly answer multi-dimensional analytical (MDA) queries. The term ''OLAP'' was created as a slight modification of the traditional database term online transaction proces ...

(OLAP) and

data mining Data mining is the process of extracting and finding patterns in massive data sets involving methods at the intersection of machine learning, statistics, and database systems. Data mining is an interdisciplinary subfield of computer science and ...

. 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 data. It defines a set of rules for encoding electronic document, documents in a format that is both human-readable and Machine-r ...

SOAP Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...

and

HTTP HTTP (Hypertext Transfer Protocol) 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 Web, wher ...

. XMLA is maintained by XMLA Council with

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

, Hyperion and SAS Institute 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, DMX or

SQL Structured Query Language (SQL) (pronounced ''S-Q-L''; or alternatively as "sequel") is a domain-specific language used to manage data, especially in a relational database management system (RDBMS). It is particularly useful in handling s ...

. * 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 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