1. A method comprising the computer-implemented steps of: a relational database server receiving a relational database statement that specifies a first expression and a second expression, wherein at least a part of said relational database statement is expressed in a first language supported by said relational database server; wherein said first expression specifies to extract data from n-dimensional data objects stored in a database according to a multidimensional schema and present said extracted data as rows; wherein said second expression includes a multidimensional expression that specifies a multidimensional operation, wherein said multidimensional expression is expressed in a second language supported by a multidimensional database server; said relational database server causing said multidimensional database server to compute said first expression, said computation of said first expression returning to said relational database server: (1) a set of rows, each row of said set of rows containing particular data derived from one or more n-dimensional objects, and (2) a mapping that maps each row of said rows to a location, of the respective particular multidimensional data, in said one or more n-dimensional objects; said relational database server causing said multidimensional server to compute second results for said second expression using said set of rows and said mapping resulting from the computation of said first expression as input to the second expression and returning said second results to the relational database server; and wherein the method is performed by one or more computing devices.