SAP R3 like other modern day ERPs uses the document principle. The document principle simply means that the R/3 system records atleast one document for every business transaction. In other words, each transaction in SAP R/3 can be traced back to a unique document with the help of a document number. Each document created in SAP R3 system is assigned a unique document number. The document number can assigned by SAP R3 automatically using internal number ranges or users themselves can assign document number using external number ranges.
To help you understand better, each document in SAP can be dentified using a document number, company code and fiscal year. Some business events result in the creation of more than one document in SAP. Depending upon the type of business transaction, SAP system decides what documents need to be created. For example, receipt of inventory may result in the creation of an inventory document as well as an accounting document for tracking financial GL information. SAP R3 is unique in the sense that it links related documents so as to provide a complete picture of a transaction within the SAP R/3 system. More on the SAP documents in my next post.