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In many cases, when the user must choose a value for a parameter from a long list, it is convenient to approximate the search in several steps.

In the case studied in this tutorial, we have so far defined a parameter to filter the report for a given salesperson. One way to facilitate the location of the salesperson, is to catalogue him first either as Distributor or Direct Sale.

In this way we could first request the Channel and later on, choose the salesperson from the list of salespeople in that channel 

This section explains how to establish this dependence between parameters through Cascading Parameters.  

Creating Cascading Parameters

1. Create a Data Set to build the list of channels.

   Name:	Channels
   Data Source:	O3 Local MDX
   Data Set Type:	O3 Data Set
   Query	SELECT {[Vendedores].[Canal].members} ON COLUMNS FROM [Vinos]

2. Create a Data Set to build the list of Salespeople in each Channel.

   Name:	ChannelSalespeople  (VendedoresDelCanal)
   Data Source:	O3 Local MDX
   Data Set Type:	O3 Data Set
   Query	SELECT {[Vendedores].?.children} ON COLUMNS FROM [Vinos] The query mark will be later associated to the parameter that identifies the Channel. Ignore any error message displayed due to not being able to solve the parameter.

3. From the Data Explorer pane right-click on the Report Parameters element.
4. Create a new Cascading Parameter 
   
5. Enter Channel Salespeople (Vendedores Del Canal) as Parameter name 
6. Select Multiple Data Set
   One Data Set will be used for each step of the parameter ( Data Sets were created before)
   
7. Press the Add button to add a parameter to the cascade.
8. Enter the following parameters for the first Parameter:  

   Name:	Channel
   Data Set:	Channels
   Value:	unique_name
   Display Text:	label

9. Press the Add button to add a second parameter to the cascade.
10. Enter the following data for the second Parameter.  

    Name:	ChannelSalesperson (VendedorDelCanal)
    Data Set:	ChannelSalespeople (VendedoresDelCanal)
    Value:	unique_name
    Display Text:	label

11. The cascading parameter editor should look as shown below.
    
12. To continue, press OK.

Relating Cascade Parameters 

So far we have defined a Cascade with 2 parameters and 2 Data Sets, one for each parameter in the cascade. 

What is left is to relate parameters so that one acts on the other. 

1. Edit the Data Set ChannelSalespeople (VendedoresDelCanal)
2. Add a parameter as shown below.
   

Testing what we have done so far.

To test what we have done so far create a new Data Set  with the following data:

   * Name: Sales by Channel and Salesperson 
   * Data Source: O3 MDX View
   * Data Set Type: O3 Data Set
   * Query The following expression in MDX:

SELECT
	{[Vendedores].?} ON COLUMNS,
	{[Vinos].[Vino].members} ON ROWS
FROM [Vinos]
WHERE Measures.[Litros Vendidos]

Create a table with the information of Sales by Channel (Vents por Canal) and Salesperson (Vendedor) as explained in Designing Report Layout

Select Preview and the following screen will appear      
                    


In Channel (Canal) all the channels of salespeople of the Wines (Vinos) cube will appear; choose a channel and Salesperson by Channel ( Vendedor Por Canal ) will automatically be updated.

In Salesperson by Channel  all the salespeople in the selected channel will appear; select one salesperson and press OK to see the detail of the litres of wine sold by this salesperson. 
For instance, if you choose "Direct Sale" as channel and Federico Moreira as Salesperson, the report will show:


|| Vino || Litros Vendidos ||

 If you wish to change the value of the parameter you will have to click on Show Report Parameters  and the previous window will be opened again, where you can choose a new channel and salesperson.

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