|ABAP is a SAP programming language and forms the backbone of most SAP BW and SAP ECC applications.
Thanks to its continuous further development towards a language focused on object-oriented components, today, ABAP is on the same level as languages such as JAVA or C#.
A SAP transport is a package which is used to transfer data from one SAP installation to another. This data can range from a simple printer driver to a whole SAP client. It can be considered as an "update", with the only difference being that SAP transports are made by the SAP users themselves.
Transports can also be used to transfer data from external applications.
Business Application Programming Interface (BAPI)
It is a remote-enabled function module which is provided by SAP. BAPIs enable access to SAP functions across formal, stable and dialog-free interfaces. These interfaces can be used by external applications developed by customers and complementary software partners as well as by other SAP applications. Defined as API methods of SAP Business Object Types, these object types are used within the Business Framework to enable object-based communication between components.
Business objects and their BAPIs enable object orientation to be used in central information processing in companies.
For example, existing functions and data can be re-used, trouble-free technical interoperability can be achieved and non-SAP components can be implemented.
Applications can use BAPIs to directly access the application layer of the R/3 System and, as clients, applications can use the business logic of the R/3 System. BAPIs provide the client with an object-oriented view of the application objects without needing to know the implementation details. BAPIs are always developed by defining scenarios which are used to map and implement system-wide business processes.