There is a lot of difference between the Enterprise Resource Planning system and the Enterprise System. Here you go with the definitions of both:
ERP: An Enterprise Resource Planning system is nothing but application software which can integrate all the functional department s of any enterprise or organization. The integration starts from sales, purchase, production, inventory, finance and ends with human resources department. It streamlines the communication process between all these functional departments.
Enterprise System: Enterprise System is integrated application software used to support data analysis, reports analysis and streamline the information flow internally in the company. Normally it is a combination of all enterprise software applications such as Enterprise Resource Planning (ERP), Customer Relationship Management (CRM) and Supply Chain Management (SCM).
Enterprise System is integrated with business applications like data warehousing and business intelligence which is used to generate the reports. It is a high end application used in the most complicated working environments.
ERP will be used in most of the medium scale companies to big companies to integrate their business process where as Enterprise System is restricted for only big and complex environments. Big companies cannot fully function with the help of ERP because there are many other functions like customer relationship management reports analysis are not be included in the software.
This is the biggest reason why big companies always look for integrated application software called Enterprise Systems. They will help the big customers in providing the management information generated by the business intelligence.
ERP role is restricted when you compare with the Enterprise Systems; it does not take care of the vendor and the customer relationships. So, apart from ERP, the customer needs to do for other applications like customer relationship management and supply chain management. But these two specialized applications may not be required for medium scale companies where in the business process and operations are restricted.
A large organization with complex working environment cannot afford to go with the ERP alone because the role of this software is limited to some extent. If the big organization which expects all the reports from all the vendors and the suppliers and internal process, it has to go with the Enterprise Systems.
Enterprise Resource Planning application has got its own role to play and it is very important to streamline the internal process only. It will not take care of the outside happenings of the organization. If a raw material comes into the organization, ERP will take care of planning and producing the end product out but it does care about the customer and raw material supplier where as the Enterprise System will take care of the end to end business process of organization because it is integrated with other applications like CRM and SCM.
It depends on the customer requirement to pitch the solution. If the customer wants to streamline entire process starting from the supplier, production and the customer, he has to go ahead with Enterprise System.