Is the integrated management of main business processes, often in real-time and mediated by software and technology.

ERP is usually referred to as a category of business management software - typically a suite of integrated applications that an organization can use to collect, store, manage and interpret data from many business activities.

Is a production planning, scheduling, and inventory control system used to manage manufacturing processes. Most MRP systems are software-based, but it is possible to conduct MRP by hand as well. 

Is the strategic approach to the effective management of people in a company or organization such that they help their business gain a competitive advantage. It is designed to maximize employee performance in service of an employer's strategic objectives