Dynamic graphical database query interface

A graphical query interface provides visual feedback to a user during the construction of a query. In a first embodiment, the visual feedback helps the user determine the quality of the query as the query is being built. The relationship of columns in the database is graphically displayed to a user. When the user selects a column in the database, a filtered display mechanism displays only those columns or records that satisfy the portion of the query already constructed. In a second embodiment, the visual feedback eliminates some possible selections in the query tree due to previously-made selections that eliminate the eliminated selections as possibilities. In the second embodiment, the visual feedback mechanism may function according to data values in columns, and may also function according to known relationships between columns themselves.