Methods and apparatus for improving data warehouse performance are disclosed. An example method to transform a first database into a second database includes generating a first mapping file associated with a fact table of the first database, the first mapping file referenced by a first hierarchical directory file path, generating a second mapping file associated with a dimension table, the second mapping file referenced by a second hierarchical directory file path, and retrieving data from the second database using the first and second mapping files via sequential navigation of the first and second hierarchical directory file paths.