Thursday, May 21, 2009

Connect Microsoft SQL Server from olap4j

Browsing my Google Analytics statistics, I realized there is a lot of people out there that are searching for ways to connect Microsoft SQL Server with olap4j.

Here is a nice example.

// We must use the XMLA driver.

// This code is for Java 5. With Java 6, you can directly
// unwrap the underlying connection with the .unwrap() call.
OlapConnection connection =
(OlapConnection) DriverManager.getConnection(

// This is the SQL Server service end point.

// Tells the XMLA driver to use a SOAP request cache layer.
// We will use an in-memory static cache.
+ ";Cache=org.olap4j.driver.xmla.cache.XmlaOlap4jNamedMemoryCache"

// Sets the cache name to use. This allows cross-connection
// cache sharing. Don't give the driver a cache name and it
// disables sharing.
+ ";Cache.Name=MyNiftyConnection"

// Some cache performance tweaks.
// Look at the javadoc for details.
+ ";Cache.Mode=LFU;Cache.Timeout=600;Cache.Size=100",

// XMLA is over HTTP, so BASIC authentication is used.
"password" );

// We can execute a query. MDX of course.
CellSet set = connection.createStatement().executeOlapQuery(

Update : Some useful links

Wednesday, May 20, 2009

PAT 0.3 - Integration and nifty features…

Pentaho Analysis Tool sprint 2 is now over and released since a few weeks. We're currently in the process of wrapping up the third sprint. What's new? What new features will there be?

Nothing very spectacular really. Yet there are a few nice features worth mentioning.

  • Integration with the Pentaho BI server
    PAT can now run embedded in the Pentaho User Console and be configured remotely. It only supports XMLA connections for this first draft, but don't worry; more compatible connection types are to be supported in the medium term. This also means that you can seamlessly use any XMLA provider. Sql Server? Essbase? Mondrian? You choose. All that thanks to olap4j. If you want specific details on this, Gretchen Moran has written a bunch of documentation on this. Congratulations to Paul Stoellberger and Gretchen Moran for this feature.

  • Create multiple queries at once
    This was a requirement that was passed to us by Pentaho's engineering team. People want to build and use more than one query at a time without concurrency issues. That was not properly supported by the age old JPivot application. Now and then we encountered some problems with multiple queries, so this was something pretty high on our features list. The backend supported that since sprint 1 , but there was higher priorities for the GUI components.

  • OlapTableModel first draft
    The Java API doesn't include a proper TableModel for OLAP data, so we're planning to write one. We still have lots of things to figure out on this subject, but we're planning to mock a draft specification before the sprint 3 deadline.

Our initial intent for the third sprint was to make the GUI nicer, but we're still trying to figure out if XUL would be a better generation tool than SWT. We are waiting for developments between the GWT-Mosaic team and Nick Baker of Pentaho and hope that all those nice gents would team up and cook something up to their talent. Fingers crossed here. :)

Also worth mentioning,  we started talks to review the Query model currently residing in olap4j. This is a soon to be major component as it will provide developers and GUI enthusiasts with a properly abstracted API to build queries against a data warehouse. Olap4j is  very great API for low level stuff, but it still needs an abstraction layer for the common folks. Building queries should not require in-depth knowledge of MDX, for you cannot expect all business analysts to master MDX anyways. Anyone who wants to participate in the process is warmly invited to manifest himself. We are really looking for input on this, whatever your background is. (As long as it's related to BI I guess...)