OLAP Schemas

Overview

A SAS OLAP schema represents a group of cubes in the SAS metadata and specifies which group of cubes an OLAP server can access. An initial OLAP schema is assigned to a SAS OLAP Server when that server is defined in the metadata. Although you can have multiple schemas, a server can access only the cubes in one schema at a time. As a result, you do not need to create more OLAP schemas than there are OLAP servers on your system.

Once an OLAP schema is available, a cube can be assigned to that OLAP schema during the cube building process. Whereas there are no absolute restrictions for the number of cubes per OLAP schema, assigning a large number of cubes to a schema should be avoided. This is because the cubes compete for the OLAP server's cube cache and data cache at the time they are accessed and handled by the server.

You can create and maintain OLAP schemas in SAS OLAP Cube Studio or SAS Management Console. Here are some of the tasks that you can perform:

Defining an OLAP Schema

In addition to SAS Workspace Server and SAS OLAP Server definitions, you must also have an OLAP schema defined in the active metadata server. The standard SAS deployment process creates an OLAP schema named SASApp - OLAP Schema and assigns it to the SAS OLAP Server that is also configured during deployment. To define new schemas, you can use the New OLAP Schema Wizard, which is available from SAS OLAP Cube Studio and SAS Management Console. In SAS Management Console, you can launch the OLAP Schema Wizard when you view the OLAP Schema tab on the Properties dialog box for an existing server. These steps explain how to use SAS OLAP Cube Studio to launch the OLAP Schema Wizard and define a new schema:

Connect to the SAS Metadata Server.
Select FileNewOLAP Schema.
On the General page of the New OLAP Schema Wizard, enter the schema name and description. Click Next.
On the Server Assignment page, specify the OLAP servers that can access the schema. This step is optional. Click Next.

Note: If you choose not to specify the server using the OLAP Schema Wizard, you can add that information later by modifying the schema's properties.
On the Finish page, click Finish.

Note: When defining a new SAS OLAP Server, if you accept the default definition settings, then an OLAP schema is automatically created and assigned to the server. To change that assignment to a different OLAP schema, you must edit the server definition. In SAS Management Console, select the Server Manager plug-in to make these changes.

Editing an OLAP Schema

The OLAP schema specifies which group of cubes an OLAP server can access. To edit an OLAP schema in SAS OLAP Cube Studio, complete these steps:

In the Tree View, select the OLAP schema that you want to edit. Then select Properties from the Edit menu or from the schema's context menu.
In the Properties dialog box, make changes on the General and Server Assignment tabs.

You can view cubes assigned to the schema on the Cubes tab. To change the OLAP schema assignment for a cube, you must select the properties for a cube and select the Location tab. From here you can enter the name of a different OLAP schema.
When you are finished, click OK on the Properties dialog box.

Changing the OLAP Schema for a Cube

When working with SAS OLAP Cubes, it might be necessary to assign a cube to a different schema. You can change the OLAP schema assignment for a cube by selecting Change OLAP Schema from the Actions menu or the cube's context menu. The Change OLAP Schema dialog box appears. The selected cube is currently assigned to the OLAP schema that is listed in the dialog box.

Select an OLAP schema from the drop-down list of OLAP schemas. If needed, you can also create a new OLAP schema by selecting the New button. This opens the New SAS OLAP Schema wizard. After you have selected an OLAP schema, select the OK button. The cube is now assigned to the selected schema.

Note: When reassigning a SAS OLAP cube to a different OLAP schema, be careful to note which OLAP server the schema is assigned to.

Deleting OLAP Schemas

To delete an OLAP schema, complete the following steps:

In the Tree View, select the schema that you want to delete.
Select Delete from the Edit menu or from the schema's context menu.
Click Yes on the Confirm Delete dialog box.

Note: You cannot delete a schema that currently has OLAP cubes assigned to it. In addition, you must have the necessary authorizations.

Viewing the OLAP Schema Properties

In SAS OLAP Cube Studio, you can view the properties for a SAS OLAP schema by selecting the schema from the Tree View and then selecting the Properties function. The Properties function can be accessed from the Edit menu and from the schema's context menu. The OLAP Schema Properties dialog box contains tabs that provide general information as well as information that is specific to SAS OLAP schemas. The following tabs are specific to OLAP schemas:

Server Assignment

lists the OLAP servers defined in the current metadata. On the Server Assignment tab, you can select an OLAP server from the Available list and move it to the Selected list.

Cubes

lists cubes that are assigned to the current schema. The Cubes tab also displays whether the cubes physically exist or exist as metadata only.

Assigning the OLAP Schema with the OLAP Procedure

To assign an OLAP schema, you must use the OLAP_SCHEMA= option with the METASVR statement. Here is an example of the METASVR statement and the OLAP_SCHEMA= option:

  METASVR
     HOST  = "hw4195.ec.sas.com"
     PORT   = 8561
    OLAP_SCHEMA = "SASApp - OLAP Schema";

Note: For more information about SAS OLAP schemas see “Managing OLAP Cube Data” in the SAS Intelligence Platform: Data Administration Guide.