Introduction On SAP

SAP was founded in 1972 in Walldorf, Germany. It stands for Systems, Applications and Products in Data Processing. Over the years, it has grown and evolved to become the world premier provider of client/server business solutions for which it is so well known today. The SAP R/3 enterprise application suite for open client/server systems has established a new standards for providing business information management solutions. 

SAP product are consider excellent but not perfect.  The main problems with software product is that it can never be perfect.
The main advantage of using SAP as your company ERP system is that SAP have a very high level of integration among its individual applications which guarantee consistency of data throughout the system and the company itself.
In a standard SAP project system, it is divided into three environments, Development, Quality Assurance and Production.
The development system is where most of the implementation work takes place. The quality assurance system is where all the final testing is conducted before moving the transports to the production environment.  The production system is where all the daily business activities occur.  It is also the client that all the end users use to perform their daily job functions.
To all company, the production system should only contains transport that have passed all the tests.
SAP is a table drive customization software.  It allows businesses to make rapid changes in their business requirements with a common set of programs.  User-exits are provided for business to add in additional source code.  Tools such as screen variants are provided to let you set fields attributes whether to hide, display and make them mandatory fields.
This is what makes ERP system and SAP in particular so flexible.  The table driven customization are driving the program functionality instead of those old fashioned hard-coded programs.  Therefore, new and changed business requirements can be quickly implemented and tested in the system.
Many other business application software have seen this table driven customization advantage and are now changing their application software based on this table customizing concept.
In order to minimized your upgrading costs, the standard programs and tables should not be changed as far as possible.  The main purpose of using a standard business application software like SAP is to reduced the amount of time and money spend on developing and testing all the programs.  Therefore, most companies will try to utilized the available tools provided by SAP.