dimension

SSAS Joining Facts at different granularity to a single dimension:

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Problem:

You have a Fact Sales and Fact Target in your data mart. Fact Sales stores values are product sub category level and fact target stores values at product category level because business sets “sales targets” at a higher (rolled up) level. How do you connect it to a single dimension at different granularity?

Solution:

Here’s the table structure, I just made this up for the demo purpose:

Fact Sales Table

1. Fact Sales

Fact Target

2. Fact Target

Product Sub Category Table

3. Dim product sub category

so, you went ahead and tried testing by creating relationship’s to single dimension at different granularity in the cube:

SSAS Dimension Usage RelationshipsNote how the relationship was specified between Fact Target and Product Sub Category Dimension – it’s joined at a different granularity compared to fact sales. it would be help you from a performance standpoint if the fields that you are using to join the fact and dimension is an int.

SSAS Relationship Dimension Usage Regular

So, you browse the cube and here’s what you get:

Excel SSAS Analysis Services

Note the problem: the target values are being repeated for sub categories but that shouldn’t be happening, right? that’s misleading to business users…ok, to recap what we need to do here: hide target values for subcategories since targets are not set at that granularity. but we do need to show them if the business users pulls in product category.

So here’s a measure group property that comes to the rescue!

Go to Fact Target Measure group’s property > Set IgnoreUnRelatedDimension to False

SSAS Ignore Unrelated Dimension Property

deploy and browse your cube again, here’s what you will see now:

Excel SSAS Analysis Services Pivot Table

That’s it! you have successfully joined facts at different granularity to a single dimension.

SQL Server Analysis Services (SSAS) multidimensional cube: How to create a role playing dimension?

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Summary:

I was recently asked by a SSAS developer about how to set up a role-playing dimension so I did a brief demo to show how to set it up. In this post, I am document the steps to help you get started:

What is role-playing dimension?

What if you want to see sales data by Order Date as well as Shipped Date? You can one date dimension that is used more than once for seeing sales data by order date and shipped date. In this case, date dimension becomes a Role Playing Dimension.

Steps:

1. Open SQL Server Data Tools and SSAS project that you are working on.

2. Go to Data Source Views from the solution explorer.

3. Make sure that the relationships are specified between dimension (e.g. date dimension) and Fact Table (e.g. Fact Sales). Example: If you’ve OrderDateSK and ShippedDateSK in your fact table, then establish a relationship between the both columns with the Primary Key of the Date dimension.

SSAS Data Source View Role playing dimension

Note: If you do not have the relationships specified in the data source views, there’s an alternative to go to dimension usage for a cube and setup role playing dimensions. since this is targeted to get you started, I am not covering the steps for that.

4. Now go to the Dimensions section in the solution explorer and add a Dimension that uses the existing data source view from step #3.

5. switch to Cubes.

Now, if you don’t have a cube created yet then you can use the cube wizard if you want and as long as you have the relationships specified at DSV’s, it should create a role-playing dimension.

Alternatively, you can also create a new dimension. In the Design pane, lower left section, you’ll see dimensions.

Add Dimensions Cube SSAS

select your dimension that you created in step #4 that’s a role-playing dimension from the list and click on OK. And it creates a role-playing dimension for you! So all you had to do was to make sure the relationships are created between the fact and (role-playing) dimension table and SSAS does the rest of the work for you

SSAS Role Playing Dimension

 

Note: for the demo I didin’t rename the dimension attributes but you do all that good stuff too when you are building the cube for users!

Conclusion:

In this post you got started on how to add a role-playing dimension in a SSAS cube.