1. A method for generating an SQL query from a frame representation, the method comprising: (a) receiving an input signal; (b) providing a frame representation of a primary object with a typed feature structure comprising typed features with feature values including a first empty feature value of a first empty feature, a first complex feature value of a first complex feature, and a first non-empty feature value of a first non-empty feature, the first complex feature value being defined by a first embedded object, the first non-empty feature value being provided by the input signal; (c) providing a relational database having a structure isomorphic to the typed feature structure of the frame representation, the relational database comprising a record with a field value corresponding to the first non-empty value of the frame representation and a record with a field value corresponding to a value of the first empty value of the frame representation; and (d) generating the SQL query for determining the first empty feature value from the first non-empty feature value based on the structural relationship of the relational database and the frame representation.