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Hitachi Vantara Lumada and Pentaho Documentation

Pentaho Schema Workbench

With a physical multidimensional data model in place, you must create a logical model that maps to it. A Mondrian schema is essentially an XML file that performs this mapping, thereby defining a multidimensional database structure. You can create Mondrian schemas using the Pentaho Schema Workbench.

In a very basic scenario, you will create a Mondrian schema with one cube that consists of a single fact table and a few dimensions, each with a single hierarchy consisting of a handful of levels. More complex schemas may involve multiple virtual cubes, and instead of mapping directly to the single fact table at the center of a star schema, they might map to views or inline tables instead.

All of the Mondrian XML elements are documented in this section in both a single quick reference list and a full individual reference piece for each element. Primarily you will be using Pentaho Schema Workbench to create Mondrian schemas graphically, though you can do advanced schema design through the Data Source Wizard in the User Console or through Schema Workbench later on.

Get Started with the Schema Workbench

Before you start using Schema Workbench, you should be aware of the following points:

  • You start Schema Workbench by executing the /pentaho/design-tools/schema-workbench/workbench script. On Linux and OS X, this is a .sh file; on Windows it's .bat.
  • You must be familiar with your physical data model before you use Schema Workbench. If you don't know which are your fact tables and how your dimensions relate to them, you will not be able to make significant progress in developing a Mondrian schema.
  • When you make a change to any field in Schema Workbench, the change will not be applied until you click out of that field such that it loses the cursor focus.
  • Schema Workbench is designed to accommodate multiple sub-windows. By default they are arranged in a cascading fashion. However, you may find more value in a tiled format, especially if you put the JDBC Explorer window next to your Schema window so that you can see the database structure at a glance. Simply resize and move the sub-windows until they are in agreeable positions.

Add a Data Source

Your data source must be available, its database driver JAR must be present in the /pentaho/design-tools/schema-workbench/drivers/ directory, and you should know or be able to obtain the database connection information and user account credentials for it.

Follow the below process to connect to a data source in Schema Workbench.

  1. Establish a connection to your data source by going to the Options menu and selecting Connection. The Database Connection dialog appears.
  2. Select your database type, then enter in the necessary database connection information, then click Test. When you've verified that the connection settings work, click OK. The database connection information includes the database name, port number, and user credentials. If you don't know what to type into any of these fields, consult your database administrator or database vendor's documentation.

    The Require Schema check box, when selected in the Options menu, puts Schema Workbench into a mode where unpopulated elements appear in the schema.

    If you are using an Oracle data source, selecting Require Schema will dramatically improve your Analysis schema load time.

  3. If you required a database schema in the previous step, you must now define it by going to the Options section of the database dialogue, and creating a parameter called FILTER_SCHEMA_LIST with a value of the schema name you want to use.

Your data is now available to Schema Workbench, and you can proceed with creating a Mondrian schema.

Remove Mondrian Data Sources

As you phase out old analysis schemas, you will have to manually remove their data source entries in the Data Source Wizard in the User Console.

  1. Login to the User Console with administrator credentials.
  2. On the Home page of the User Console, click Manage Data Sources. The Data Source Wizard appears.
  3. Click to highlight the data source to be deleted, and click Remove.

The data source is removed and is no longer available for use.