Can somebody please tell me what multidimensional data means? I need tom consume data from a Data Cube [SSAS] MDX Query and populate it in a win form, any know hows?
Dinesh
You can start by reading a quick tutorial to MDX : Gentle introduction to MDX
After you'll need a library to access your OLAP server (In Java Olap4J, in .NET you've ADOMD)
Related
Hi guy i'm newbie for Pentaho tool. Now i have some data source look like this
And i want to apply my data with this chart
I see a documentation already but I not understand every thing. Can some tell me some tip or solution please. Thank a lot
Microsoft introduced MDX for analysis services and since then few things have changed in the market place. Microsoft now have column store analysis services tabular and power pivot that run on DAX. Also database vendors have moved to in-memory (SAP Hana). I have long given up on MDX as unnecessary in the current DAX tabular environment, however SAP HANA excel pug-in now uses MDX to query HANA models and I'm trying to access if its worth learning MDX again.
Thanks
Using MDX is one of several options to query SAP HANA information models.
Standard SQL queries would do just as well.
MDX is mainly aimed at providing a common interface language to access data sources and return the data into multi-dimensional structures.
It also provides several language concepts not covered by SQL, e.g. hierarchy processing.
I've yet to see a user that would write his MDX statements for ad-hoc reporting by hand...
I work for a company that has a very mature and precise olap environment - MDX is 100% relevent.
We will start to look to move certain functionality into the Tabular/DAX world but I wouldn't imagine stopping MDX for a good while.
To me it is a very pretty declarative language - elegant and powerful - much more so than sql or what I've so far seen of DAX.
If sql is checkers(draughts) then mdx is chess!
From what I gather, MDX is typically used for OLAP multidimensional data stores. In SSAS 2012, it looks like DAX is used for tabular models, but MDX is supported as well. So why are there two query languages available for one system? Furthermore, which is the recommended one to use for tabular model and why? Is DAX faster than MDX in these scenarios?
I've yet to install or play with SSAS 2012 yet so if I might be missing something.
DMX is a data mining query language, which you use to identify inherent patterns in the data. User Smith is correct regarding which languages can be used on which platform. DAX utilises the xVelocity in-memory analytics engine which performs faster on average than the multidimensional cube technology (ROLAP, MOLAP). MDX is not as fast as DAX queries on a tabular model.
I don't have all the answers but from my understnading this is how it goes.
MDX is for the developer.
DAX is for the superuser (excel user/ business user).
Microsoft thought that MDX was too complicated for a business user so they conjured up DAX which is very similar to Excel functions, and they thought it would be quick for the end user to catch on to this if they were already familiar with Excel.
I don't know which is necessarily faster, I think it is more about what you are comfortable using. Personally, I use both languages, but I really only tend to use DAX in powerpivot and excel (obviously). So, I am more comfortable using MDX wherever I can.
HTH, oh and by the way there is also DMX which I have yet to use but believe this can also be used with SSAS. And yes I agree two/three query languages for one system is a pretty confusing thought but once you read up on it and use them a bit it makes a little more sense because their situational usage is so much different.
I want to build an dashboard for which back end will be Pentaho community edition. I am using Mondrian and MDX queries.
I have tried to use Pentaho CDF for building dashboard but it seriously lacks documentation and without proper documentation its not possible to build dashboards. I am facing problem with lot of small things.
For example, I wrote one MDX query which returns sum of sales and expenses for each of the department. This MDX query works fine in Analysis view .
In Analysis view I am able to see bar chart different bars for sales and expenses. Then I used same MDX query in datasource of type MDX over MondrianJNDI CDE dahboard type and attached this datasource to CCC Bar Chart but CCC Bar Chart is displaying values for only sales.
So I would like to know how can I display same bar chart as I get in Analysis view?
Also, I would like to know how to create parametrized MDX query in Pentaho CDF? How to use Dashboard Chart Java API?
I am finding it difficult to use Pentaho CDF, so I want to try other API or framework for building dashboards. What are other options available in this kind of scenario?
Please enlighten,
Thanks in Advance !!!
(disclaimer: I'm the lead developer for the CTools in general, and CDF in particular)
You'll find that CDF is indeed the most popular choice within the Pentaho community, and that in turn means that it's what the community itself will have the easiest time helping you with. Since your issue is documentation, I'm not sure how much you've explored what's already there. If you have Pentaho installed, from the Pentaho User Console head to the BI Developer Examples solution folder, and under CDF you'll find the CDF Documentation.
Alternatively, I suggest you give CDE a try (CDE is an editor that builds dashboards on top of CDF and CDA). You'll find a great tutorial for it here.
(disclaimer:I'm working for icCube).
If you're keen going for a no free solution you can try icCube OLAP server and their GVI library. It's on the starting blocks but interesting if you want to build your own solution. You can see some examples here.
If you need support, paying for a little support it's a money and time saving solution (this for any solution you take). Community is nice, but there is a limit on the time people can spend helping other for free.
I would like to know more about "MDX" (Multidimensional Expressions).
What is it?
What is it used for?
Why would you use it?
Is it better than SQL?
What is its use in SAP BPS (I haven't seen BPC, just heard that MDX is in it and want to know more)?
MDX is the query language developed by Microsoft for use with their OLAP tools. Since its creation, others (The open source project Mondrian, and Hyperion) have tried to create versions of it for use in their products.
OLAP data tends to look like a star-schema with a central fact table surrounded by multiple dimensions. MDX is designed to allow you to query these structures and create cross-tab type results.
While the language looks like SQL it doesn't behave like it and if you are an SQL programmer, the mental leap can be tough.
As to whether it is better than SQL, it serves a highly specialized purpose, i.e. analyzing data in a specific format. So if you want to query a star schema, it is better, otherwise, SQL will probably do the job.
MDX means Multi Dimensional eXpressions or some such. It is relevant to OLAP cubes and not to regular relational databases such as Oracle or SQL Server (although some SQL Server editions come with Analysis Services which is OLAP). The multidimensional world is about data warehousing and efficient reporting, not about doing normal transactional processing so you wouldn't use it for an order entry system, but you might move that data into a datamart to run reports against to see sales trends. That should be enough to get you started I hope.
SQL is for 'traditional' databases (OLTP). Most people learn the basics fairly easily.
MDX is only for multi-dimensional databases (OLAP), and is harder to learn than SQL in my opinion. The trouble is they look very similar.
Many programmers never need MDX even if they have to query multi-dimensional databases, because most analysis software forces them to build reports with drag-drop interfaces.
If you don't have a requirement to work with a multi-dimensional database, then don't create one just for the fun of it.....it won't be...
There are 2 versions of SAP-BPC (Business Objects Planning and Consolidation)
SAP-BPC Netweaver
SAP-BPC Microsoft Analysis Services
The Microsoft analysis services version of the product allows you to use MDX or multi dimensional expressions to both query the multi-dimensional database (OLAP) and write calculation logic.
However, SAP-BPC does not require a knowledge of MDX to either be used or administered.
You can see product documentation and a demonstration.
Best of luck on your research,
Focused on SAP BPC:
What is it used for?
It's used when you want to apply some custom calculation/business logic over many records/intersections and after submitting raw data. Example, first send prices in one input schedule, then quantities in other one, as a third step run a calculation for sales amount based on prices and quantities for all products.
It's also used to execute the Business Rules, for that you run a predefined program (like CALC_ACCOUNT, CONSOLIDATION, etc)
Is it better than SQL?
In BPC, "SQL" logic scripts have better performance than MDX. However SQL for BPC purposes has not much to do with SQL used in other it's just how they call it.
You will get a good start by just searching for MDX in the search box up top.