Abstract: In accordance with an embodiment, described herein is a system and method for extending a semantic model, for use with an analytic applications, analytics cloud, or other type of business intelligence or data analytics environment. A semantic model extension process introspects a customer's data, for example as stored in a data warehouse instance, and evaluates metadata associated therewith to determine custom facts, custom dimensions, and/or other types of data source model extensions. A payload or indication of such extensions is used to extend or customize a semantic model that enables surfacing of business intelligence or data analytics at a presentation layer. In accordance with an embodiment, the system can include an administrative console application and user interface that allows a user to view and validate a customer's data as loaded from their source environment into a data warehouse instance for use with other types of data analytics environments.