There are several ways. If you have a fixed set of queries which you'd like to display as HTML tables, use the tab library. webapp/taglib.jsp is an example of this.
The JPivot project (http://jpivot.sourceforge.net) is a JSP-based pivot table, and will allow you to dynamically explore a dataset over the web. It replaces the prototype pivot table webapp/morph.jsp.
Pentaho Analysis Tool is an AJAX-based client.
You could also build a pivot table in a client technology such as Swing.
Mondrian's main API is olap4j., an extension to JDBC for OLAP applications.
Mondrian also has a provider for XML for Analysis.
Historically, Mondrian had its own API, consisting of classes in the mondrian.olap package. That API has been deprecated since mondrian-3.0, and may change or be removed without warning in future versions. JPivot still uses it.
Not very much.
todo: User-defined functions
todo: Cell readers
todo: Member readers
Yes, if your RDBMS can. We delegate the aggregation to the RDBMS, and if your RDBMS happens to have materialized group by views created, your query will fly. And the next time you run the same or a similar query, that will really fly, because the results will be in the aggregation cache.
The syntax of the connect string is described in the Configuration guide.
We'd love to hear what you liked and didn't like about it. Post questions and comments to the forum. If you can think of ways that Mondrian can be improved, roll up your sleeves and help make it better!
If you modify Mondrian's source code, you are required by the terms of the Eclipse Public License to release your changes under that license (though not necessarily to the Mondrian project). Applications built on top of Mondrian, or plug-ins into Mondrian such as user-defined functions, do not need to be released open-source. But we'd appreciate any contributions, and of course, contributing your changes will make it easier for you to maintain your application when we release new versions of Mondrian.
I am trying to build a cube with measures from 2 different tables. I have tried a virtual cube, but it does not seem to work - it only relates measures and dimensions from the same table. Is there a way to specify that a measure is not coming from the fact table? Say using SQL select?
Virtual cubes sound like the right approach. The way to do it is to first create a dummy cube on your lookup table, with dimensions for as many columns as are applicable. (A classic example of this kind of cube is an 'ExchangeRate' cube, whose only dimensions are time and currency.)
Then create a virtual cube of the dummy cube and the real cube (onto your fact table).
Note that you will need to use shared dimensions for the cubes to join implicitly.
Use the <View> element INSTEAD OF the <Table> element. You need to specify the 'alias' attribute, which Mondrian uses as a table alias.
The XML 'CDATA' construct is useful in case there are strange characters in your SQL, but isn't essential.
Consider this scenario. I have created some tables in Oracle, like this:
and referenced it in my schema.xml like this:
Now I start up Mondrian and get an error
The problem is that table and column names are case-sensitive. You told Mondrian to look for a table called "sales", not "SALES" or "Sales".
Oracle's table and column names are case-sensitive too, provided that you enclose them in double-quotes, like this:
If you omit the double-quotes, Oracle automatically converts the identifiers
to upper-case, so the first
There are two possible solutions. The simplest is to change the objects to upper-case in your schema.xml file:
Alternatively, if you decide you would like your table and column names to be
in lower or mixed case (or even, for that matter, to contain spaces), then you
must double-quote object names when you issue
You can't just compile the source code using your IDE; you must build using
ant, as described in the build instructions. This is
because several Java classes, such as
You don't have the correct JAR files (in this case,
13.1. When I change the data in the RDBMS, the result doesn't change even if I refresh the browser. Why is this?
Mondrian uses a cache to improve performance. The first time you run a query, Mondrian will execute various SQL statements to load the data (you can see these statements by turning on tracing). The next time, it will use the information in the cache. See caching design for more information.
If the data in the RDBMS is modified, Mondrian does not know unless you tell it using the cache control API, and will continue to answer queries using stale data in its cache.
By the way, if you are using the JPivot web UI and refresh the browser, that does not help; it will simply regenerate the web page, not flush the cache.
I am using an MDX query with a calculated "aggregate" member. It aggregates the values between Node A and Node B. The dimension that it is aggregating on is a Time dimension. This Time dimension has a granularity of one minute. When executing this MDX query, the performance seems to be fairly bad.
Here is the query:
Is this normal behavior? Is there any way I can speed this up?
The performance is bad because you are pulling 19 days * 1440 minutes per day = 27360 cells from the database into memory per cell that you actually display. Mondrian is a lot less efficient at crunching numbers than the database is, and uses a lot of memory.
The best way to improve performance is to push as much of the processing to the database as possible. If you were asking for a whole month, it would be easy:
But since you're working with time periods which are not aligned with the dimensional structure, you'll have to chop up the interval:
This will retrieve a much smaller number of cells from the database — 18
days + no more than 1440 minutes — and therefore do more of the heavy lifting
Q. I saw the perforce files, but a I couldn't find where to register and get new user, or the instructions that you have mentioned above.
A. Ask the project administrators (Julian) to register you. I would suggest that you start with guest level access and let's see if you need update access later. For more information, see the developer's guide.
Q. Do you have some model for development environment (e.g. eclipse 3.4 + ant 1.7 + jboss x.x + .....)?
A. Using Eclipse for Mondrian development works fine. There is an Eclipse Perforce plug-in, too, but you can use the Perforce client outside of Eclipse. Some people use IntelliJ IDEA (which is free for open-source use).
As a test web-server, most people use Tomcat 5.5.
Q. Are all the updated documentation in the perforce server? How could I get more materials, howtos, etc. to reduce my learning curve?
A. As with any open source project, the documentation is the web site (which is source-controlled in Perforce too), the forums and mailing lists, the test suite and the code.
Also, use Google, and learn How To Ask Questions The Smart Way.
Q. How could I enroll myself into Mondrian project?
We don't give people committer rights (privilege to check directly into the perforce source code system) until they have made a few contributions. So, fix a few bugs, and post them to the developer list email@example.com. If you're thinking of implementing a major feature, discuss it with the developers before you start work, so you do it consistent with the architecture.
Author: Julian Hyde; last modified July 2010.