1. A computer-implemented method for creating an object for data access, the method comprising: defining at least one function-expression in source code using an object-oriented programming language; exposing the at least one defined function-expression in a graphical user interface of a development tool used to create the object; receiving a selection of at least one field among a list of available fields for data access; and wherein exposing the defined function-expression in the graphical user interface includes displaying the defined at least one function-expression in the list of available fields.