1. A method for defining an interface, comprising: providing an interface to a supplier over a network, the interface allowing the supplier to define a new request type based on a set of attributes and a set of parameters, the set of parameters comprising parameter names and parameter data types; receiving from the supplier a set of attribute values for the set of attributes, and a set of parameter names and parameter data type values for the set of parameters; creating a request type in a database based on the set of attribute values, and associating the set of parameter names and parameter data types with the request type; receiving from the supplier a supplier link for communicating with the supplier; and associating the supplier link with the newly created request type, thereby allowing the database to be searched for the supplier according to the request type and the set of parameter names and parameter data types, and allowing communication with the supplier via the supplier link for the request type.