  OLAP systems operate on historical data and provide answers to analysts
queries. Recent in-memory implementations provide significant performance
improvement for real time ad-hoc analysis. Philosophy and techniques of what-if
analysis on data warehouse and in-memory data store based OLAP systems have
been covered in great detail before but exploration of new dimension value
(attribute) introduction has been limited in the context of what-if analysis.
We extend the approach of Andrey Balmin et al of using select modify operator
on data graph to introduce new values for dimensions and measures in a
read-only in-memory data store as scenarios. Our system constructs scenarios
without materializing the rows and stores the row information as queries. The
rows associated with the scenarios are constructed as and when required by an
ad-hoc query.
