There are two types of logical dimensions:
Only for 11g You can expose logical dimensions to Oracle BI Answers users by creating presentation hierarchy objects that are based on particular logical dimensions. Creating hierarchies in the Presentation layer enables users to create hierarchy-based queries.
You can also transmit the hierarchy metadata from OBIEE to the underline database with the help of the sametaexport utility. From 11g.
Consists of an ordered set of two or more levels. For example, a Time hierarchy might have three levels for Year, Quarter, and Month. Level-based hierarchies can also contain parent-child relationships.
Level-based Dimension hierarchy levels allow :
Special type of level-based dimension are supported:
value-based hierarchy — Consists of values that define the hierarchy in a parent-child relationship and does not contain named levels. For example, an Employee hierarchy might have no levels, but instead have names of employees who are managed by other employees. Employees can have titles, such as Vice President. Vice Presidents might report to other Vice Presidents and different Vice Presidents can be at different depths in the hierarchy.
In addition to being level-based or parent-child, hierarchy can be one of the following.
A hierarchy in which all the lowest-level members do not have the same depth. For example, a Time hierarchy might have data for the current month at the day level, the previous month's data at the month level, and the previous 5 years' data at the quarter level. This type of hierarchy is also known as an unbalanced hierarchy.
A hierarchy in which certain members do not have values for certain higher levels. For example, in the United States, the city of Washington in the District of Columbia does not belong to a state. The expectation is that users can still navigate from the country level (United States) to Washington and below without the need for a state.
This error occur when the Leaf levels in a dimension have to be identical.
But also when you have metadata problem. You get them by using “Create a parent level” from a leaf level. Try to use “Create a child level” from the Grand Total level.