Looking more closely at ERP systems, a key factor is the integration of data from all aspects of an organization. To accomplish this, an ERP system typically runs on a single database instance with multiple software modules providing the various business functions of an organization.
Our organization - typically those with sufficient in-house IT skills to integrate multiple software products - choose to only implement portions of an ERP system and develop an external interface to other ERP or stand-alone systems for their other application needs. For instance, the PeopleSoft HRMS and Financials systems may be perceived to be better than SAP's HRMS solution. And likewise, some may perceive SAP's manufacturing and CRM systems as better than PeopleSoft's equivalents. In this case these organizations may justify the purchase of an ERP system but choose to purchase the PeopleSoft HRMS and Financials modules from Oracle, and their remaining applications from SAP.
This is very common in the retail sector, where even a mid-sized retailer will have a discrete Point-of-Sale (POS) product and financials application, then a series of specialized applications to handle business requirements such as warehouse management, staff rostering, merchandising and logistics.
ERP delivers a single database that contains all data for the software modules, which would include: Manufacturing Engineering, Bills of Material, Scheduling, Capacity, Workflow Management, Quality Control, Cost Management, Manufacturing Process, Manufacturing Projects, Manufacturing Flow Supply Chain Management Inventory, Order Entry, Purchasing, Product Configurator, Supply Chain Planning, Supplier Scheduling, Inspection of Goods, Claim Processing, Commission Calculation Financials General Ledger, Cash Management, Accounts Payable, Accounts Receivable, Fixed Assets Human Resources Human Resources, Payroll, Training, Time & Attendance, Benefits Data Warehouse and various Self-Service interfaces for Customers, Suppliers, and Employees Customer Relationship Management Sales and Marketing, Commissions, Service, Customer Contact and Call Center support Projects Costing, Billing, Time and Expense, Activity Management.