4. A method of processing a data agnostic business intelligence query against a multidimensional data source, the method comprising the steps of: detecting and intercepting a data agnostic business intelligence (BI) query issued against a multidimensional data source, wherein the data agnostic BI query combines a least one online analytical processing (OLAP) query element and at least one relational style function not natively supported by the multidimensional data source, wherein the relational style function comprises one of a date arithmetic function and a string manipulation function; decomposing an expression in the data agnostic business intelligence query into a decomposed multidimensional expression, based on the OLAP query element and a decomposed relational expression, based on the relational style function wherein decomposing the expression in the data agnostic business intelligence query includes: (i) identifying if a part of the expression in the query that is not supported by an OLAP query provider, and (ii) creating an OLAP query provider operation sub-Query based on the part of expression that is supported by the OLAP query provider; and replacing the data agnostic business intelligence query with a stack of operations expressed by the decomposed multidimensional expression and/or the decomposed relational expression for execution of the operations, wherein replacing the data agnostic business intelligence query with a stack of operations includes: (i) identifying one or more operations expressed by the decomposed multidimensional expression to send the OLAP query provider executing multidimensional query operations, and (ii) identifying one or more operations expressed by the decomposed relational expression to send to a relational query provider executing relational query operations.
5. The method as recited in claim 4 , wherein the decomposing step further comprises the steps of: extracting a relational sub-expression in the data agnostic business intelligence query into relational query data items; creating an OQP data item for each tabular data item in the data agnostic business intelligence; and replacing the relational sub-expressions OQP items.