A database including vertical tables useful for storing large numbers of objects having potentially thousands of attributes in, e.g., e-commerce applications. To support querying the vertical database using conventional SQL, a horizontal view over the underlying vertical tables is defined, and then queries are posed against the view. The queries are automatically transformed and executed against the vertical tables. If desired, the query results can be transformed back to a horizontal format. In this way, it appears to the user that a conventional horizontal data format is being used.