1. A user interface for building a formulated query to search a database of structural data organized by classes, attributes of classes, literals of attributes, and structural relations between classes, and for displaying results of the formulated query, the user interface comprising: an interface service supported by a computerized device, wherein the computerized device is a computer or other microprocessor based controller having one or more non-transitory digital data storage spaces, and wherein the interface service is configured to cause displaying of each of: a structural query section to define constraints for the formulated query, the structural query section including one or more first query elements to be populated and allowing for adding of one or more additional query elements, wherein at least one relationship between two or more of the query elements is expressible using at least one defined structural relation, wherein the query elements are graphically displayed as including element connectors by which the at least one defined structural relation can be established, and wherein the element connectors are selectable so as to allow for the adding of the one or more additional query elements to occur above, below, or in between at least some of the first query elements; and a query results section for displaying the results of the formulated query after the formulated query is executed, wherein each query element has a respective class portion which is automatically populated or populated by designating a respective one of a special class identifier and a concrete class identifier, wherein each query element further includes a respective attribute portion which is automatically populated or populated by designating a respective one of a special attribute identifier and a concrete attribute identifier, wherein the two or more query elements include a first query element and a second query element, wherein the respective class portion of the first query element is a first class portion wherein the respective class portion of the second query element is a second class portion, wherein the first class portion is populated by designating a first special class identifier that is a variable identifier signifying a user desire for one or more possible items to be identified based upon a variable input that are then available as one or more of the results, wherein the at least one defined structural relation includes a first defined structural relation, wherein the first defined structural relation expresses a hierarchical structural relationship that is a first relationship of the at least one relationship, and wherein the first defined structural relation is a contains relation according to which the second class portion of the second query element is contained by the first class portion of the first query element.