Muokkaa

Jaa

View or Change Algorithm Parameters

  • Artikkeli

Applies to: SQL Server 2019 and earlier Analysis Services Azure Analysis Services Fabric/Power BI Premium

Important

Data mining was deprecated in SQL Server 2017 Analysis Services and now discontinued in SQL Server 2022 Analysis Services. Documentation is not updated for deprecated and discontinued features. To learn more, see Analysis Services backward compatibility.

You can change the parameters provided with the algorithms that you use to build data mining models to customize the results of the model.

The algorithm parameters provided in Microsoft SQL Server SQL Server Analysis Services change much more than just properties on the model: they can be used to fundamentally alter the way that data is processed, grouped, and displayed. For example, you can use algorithm parameters to do the following:

  • Change the method of analysis, such as the clustering method.

  • Control feature selection behavior.

  • Specify the size of itemsets or the probability of rules.

  • Control branching and depth of decision trees.

  • Specify a seed value or the size of the internal holdout set used for model creation.

The parameters provided for each algorithm vary greatly; for a list of the parameters that you can set for each algorithm, see the technical reference topics in this section: Data Mining Algorithms (Analysis Services - Data Mining).

Change an algorithm parameter

  1. On the Mining Models tab of Data Mining Designer in SQL Server Data Tools, right-click the algorithm type of the mining model for which you want to tune the algorithm, and select Set Algorithm Parameters.

    The Algorithm Parameters dialog box opens.

  2. In the Value column, set a new value for the algorithm that you want to change.

    If you do not enter a value in the Value column, SQL Server Analysis Services uses the default parameter value. The Range column describes the possible values that you can enter.

  3. Click OK.

    The algorithm parameter is set with the new value. The parameter change will not be reflected in the mining model until you reprocess the model.

View the parameters used in an existing model

  1. In SQL Server Management Studio, open a DMX Query window.

  2. Type a query like this one:

    select MINING_PARAMETERS   
from $system.DMSCHEMA_MINING_MODELS  
WHERE MODEL_NAME = '<model name>'

See Also

Mining Model Tasks and How-tos