Abstract: A method of querying a database system, the database system comprising at least one database populated with a plurality of unique, multi-character expressions associated with the data entities of the at least one database, the method comprising: providing a graphical user interface for receiving at least one input selection from a user defining a database query expression; scanning the at least one database with the database query expression to obtain a first set of results; parsing the first set of results with a user profile expression associated with the user to obtain a second set of results, the user profile expression comprising a unique, multi-character expression; and displaying the second set of results in the graphical user interface.

Abstract: A method of querying a database with a graphical user interface comprising the steps of: scanning a portion of the database defining a first group, with a database query expression; generating and displaying, in response to the scanning, a set of results defining at least one sub group; allowing a user to select and store the displayed at least one sub group; and allowing a user to select the stored sub group as a group on which at least one query is to be performed.

Abstract: A method of operating a database system access to plurality of heterogeneous databases, each of said databases having a structure based on a respective database model and storing a plurality of data entities having attributes and occurrences within the structure; providing an interface database, the interface database populated with a plurality of unique, multi-character expressions associated with the data entities of plurality of databases, whereby the plurality of unique, multi-character expressions are defined by assigning to every entity, every attribute and every entity occurrence a unique, multi-character expression, the expression having a predetermined hierarchical structure which defines the relationship between each entity, attribute and entity occurrence with every other entity, attribute and entity occurrence in the interface database and storing said expressions in an expression set table linking each element of each expression to a hierarchical level and a position in a data model.