1. A computer method for merging a second schema into a first schema, wherein each schema is comprised of categories organized by a hierarchy, the hierarchy defining relationships between categories, the first schema is used as a decision tree by a customer relationship management (“CRM”) application, and both schemas are used by a plurality of application programs each having an application area, and each application area including a reference to the schemas used by the corresponding application program, comprising: responsive to receiving the first schema, comparing each path from a root of the hierarchy of the second schema with paths of the first schema and if a path does not have a corresponding path in the first schema, then adding the path to the first schema by adding those categories of the path of the second schema to the first schema that are not present in the first schema, and adding a reference to the first schema to each application area that contains a reference to the second schema.