1. [2 pts] Design an ER schema for a database application described as following: A project (identified by its unique Project-Number, a project name, and a start date) consists of several work packages (a work package is described by a unique WP-number, a description, a start date, and a due date). Work packages are structured into a hierarchical work breakdown structure, whereby a work package can be subdivided into several further work packages, while each work package is subordinated to.