ANALYSIS SERVICES TASKS
The Analysis Services tasks are provided in the SSIS environment to deal with generating and updating cubes and working with data mining projects in SQL Server Analysis Services only. Three tasks can be used for Analysis Services in SSIS: the Analysis Services Execute DDL Task, the Processing Task, and the Data Mining Task. To review the tasks in this section, you need to have installed the sample Analysis Services databases from Microsoft SQL Server.
Analysis Services Execute DDL Task
The SQL Server Analysis Services Execute DDL Task is the Analysis Services equivalent of the Execute SQL Task, but it is limited in scope to issuing Data Definition Language statements. The task simply executes a DDL statement against an Analysis Services system. Typically, you would use DDL statements to create a cube, a dimension, or any other online analytical processing (OLAP) object.
To configure the task, go to the DDL tab and select the Connection Manager that you wish to execute the DDL statement against in the Connection option. Then in the SourceType property, select whether the DDL statement will be directly inputted, pulled from a file, or pulled from a variable option. Essentially, the source type option determines whether you need to key in the DDL statement directly, provide a variable, or point to a file where the DDL statement is stored. Below Diagram shows an example of the DDL being directly entered into the SourceDirect property, which deletes a given dimension.
Note that this task can be used only to submit DDL statements. If you wish to query cubes to retrieve data, you need to use the Analysis Services Processing or Data Mining Tasks.
NOTE: You can easily find XMLA statements by going to Management Studio and scripting a given action. In the example just mentioned, you can open Management Studio and delete the dimension, but instead of clicking OK, click the Script icon.
Analysis Services Processing Task
The SQL Server Analysis Services Processing Task takes care of the processing of Analysis Services objects. If you are familiar with using the Analysis Service projects in SSDT, then you’ll be familiar with the task of processing a cube, dimension, or mining object. Configuration of the task is done in the Analysis Services Processing Task Editor in the Processing Settings tab. First, select the Analysis Services Connection Manager that you wish to process. Next, click the Add button and select the Analysis Services objects you want to process. After clicking OK, you are taken back to the Processing Settings tab, where you can change the type of processing you will be performing. To do this, right-click each object and select the process option you want. The options vary according to the type of object.
If you click Impact Analysis, analysis is performed on the selected objects, showing you the objects that will be affected by the processing. The Change Settings button enables you to configure the batch settings for the task. For example, here you can specify whether you want the objects to be processed in sequential order or in parallel and how you want errors handled.
To get a feel for how this SSIS task works, you need to download and deploy the AdventureWorks Analysis Services SSAS project from WWW.WROX.COM. This will deploy the cube and a set of dimensions that you’ll want to process periodically as new data is loaded into the warehouse. In SSIS, you can process the deployed cube using the Analysis Services Processing Task. Connect to the Analysis Services server that you deployed to, and in the Processing Settings tab select the Employee Cube and the Sales Territory dimension to process.
The Analysis Services Processing Task can then be run to reprocess the existing dimension and employee cube. These SSIS tasks enable you to periodically update your warehouse structures based on events that can be processed using an event captured by the Message Queue Task, which we cover later in the “Message Queue Task” section of this chapter.
Data Mining Query Task
The Data Mining Query Task enables you to run predictive queries against your Analysis Services data-mining models and output the results to a data source. The Data Mining Query Task is similar to the Analysis Service Execute DDL Task in that you can execute subsequent mining queries against a processed mining model in Analysis Server. The Task Editor enables configuration to a source Analysis Services server and can output the results in any ADO.NET or OLE DB Data Source. An example of the Data Mining Task configured to run a mining query against a predefined Employee Dimensional Mining model is shown in below diagram.
This task would be used to run predictive queries based on built-in prediction models in Analysis Services. The query uses a Data Mining Extension to TSQL called DMX. If you are not fluent in DMX, don’t worry, the Query tab in this task will walk you through building one. However, first you need a mining structure to query against. In the Analysis Service server, a deployed data mining model would look like the highlighted decision tree model in Figure 3-6.
The results of the prediction query can be set to return single or multi-row results and can be saved to table structures for further analysis. These results can be useful for additional SSIS packages that can integrate the predictive results into further Data Flows, but before we can step any further into these capabilities, let’s first go over the Data Flow Task itself.
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