On reason for defining and using alternate plan types is to enable the use of historical date ranges that are earlier than those in the default plan type.
The historical data source, whether default or alternate, must contain all the dimensions on either the Series or Time axis of the current Planning form. One exception is that an alternate year dimension can be specified for the Year dimension. This is useful when an alternate plan type contains earlier dates than the default.
An alternate year dimension may be used for a historical plan type which contains years prior to the start of the current Year dimension. This approach enables the addition of past historical years if the current Planning application's Year dimension does not include enough past years to meet prediction requirements. For example, if the current Year dimension covers FY08 to FY14, it may be necessary to add historical data from FY03 to FY07 for predictions. In this case, a historical plan type may be used with an alternate year dimension that contains members FY03 to FY07. The dimension name may be any valid custom dimension name, such as AltYear. For dimension requirements, see Alternate Year Dimension Requirements.
Alternate year dimensions must meet the following requirements:
The alternate year dimension is a custom Planning dimension with year members that follow the same naming pattern as the current Year dimension. For example, if the Year dimension contains FY08 to FY14, then the alternate year dimension should use FYxx as the naming pattern, such as FY03 to FY07.
The application's Year dimension cannot be included in this alternate historical plan type.
When an alternate plan type is selected as a data source and an alternate year dimension is present, the alternate year dimension will be detected automatically. A dialog is displayed that asks users if they want to use the alternate year dimension. If they respond OK, the alternate year dimension is used.
For additional information about creating alternate plan types, see About Creating Alternate Plan Types
Alternate plan types containing alternate year dimensions typically are created after the initial creation of a Planning application. They usually use the ASO storage type as this type is more efficient for large amounts of data. All plan types created during the initial Oracle Hyperion Planning application creation typically inherit the Year dimension. However, ASO plan types created after the application enable administrators and others with appropriate security roles to add dimensions selectively so that a custom year dimension can be included without the default Year dimension.