A method for XML based object-relationship mapping for different object types in a computer system is provided. The method includes creating a database schema in a database layer including a single table with specific database columns for storing known properties as well as customizable database columns for storing extended properties. The method also includes creating an object in an object layer that has specific methods for known properties and dynamic methods for extended properties, where the object types are variations of the object, the object includes fields for the properties, and the object supports reading and writing the properties to corresponding database columns in the table. The method further includes creating an XML file containing definitions for new object types and new properties, where the property definitions include database column names, and the XML file contains display information for GUI management. The method additionally includes outputting display information a GUI.