Any body explain me the differrence between BAPI and RFC

Question

Hi gurues,
               The main difference between rfc and bapi is calling the non sap system. Other than that what r the differrence . How sap modules works other machine without sap is installed.

Answer 1

The difference is not importat while you understand the concept.
I think, RFC is the protocol for calling functions from external systems in R/3.
I understand like BAPI a series of complet functions that SAP offers you for use and model a business use.
But if I need program a function that can be called for external system i would call it RFC_NAME, because is a unique function that makes a single task.
In other words, the difference i think is about work idea more than another thing.
RFC
A remote function call is a call to a function module running in a system different from the caller's. The remote function can also be called from within the same system (as a remote call).
RFC consists of two interfaces : A calling interface for ABAP Programs and a calling interface for Non-SAP programs.
The RFC Interface takes care of :-
Converting all parameter data to the representation needed in the remote system
Calling the communication routines needed to talk to the remote system.
Handling communications errors, and notifying the caller, if desired ( using EXCEPTIONS paramater of the CALL FUNCTION).
BAPI
BAPIs are standardized programming interfaces (methods) enabling external applications to access business processes and data in the R/3 System.
BAPIs provide stable and standardized methods to achieve seamless integration between the R/3 System and external applications, legacy systems and add-ons.
BAPIs are defined in the BOR(Business object repository) as methods of SAP business object types that carry out specific business functions.
BAPIs are implemented as RFC-enabled function modules and are created in the Function Builder of the ABAP Workbench.
The most critical difference btwn BAPI and FM is that BAPI can be wrapped in Business objects whereas RFC cant.
BAPI are RFC enabled function modules. the difference between RFc and BAPI are business objects. You create business objects and those are then registered in your BOR (Business Object Repository) which can be accessed outside the SAP system by using some other applications (Non-SAP) such as VB or JAVA. in this case u only specify the business object and its method from external system in BAPI there is no direct system call. while RFC are direct system call Some BAPIs provide basic functions and can be used for most SAP business object types. These BAPIs should be implemented the same for all business object types. Standardized BAPIs are easier to use and prevent users having to deal with a number of different BAPIs. Whenever possible, a standardized BAPI must be used in preference to an individual BAPI.
The following standardized BAPIs are provided:
Reading instances of SAP business objects
GetList ( ) With the BAPI GetList you can select a range of object key values, for example, company codes and material numbers.
The BAPI GetList() is a class method.
GetDetail() With the BAPI GetDetail() the details of an instance of a business object type are retrieved and returned to the calling program. The instance is identified via its key. The BAPI GetDetail() is an instance method. BAPIs that can create, change or delete instances of a business object type
The following BAPIs of the same object type have to be programmed so that they can be called several times within one transaction. For example, if, after sales order 1 has been created, a second sales order 2 is created in the same transaction, the second BAPI call must not affect the consistency of the sales order 2. After completing the transaction with a COMMIT WORK, both the orders are saved consistently in the database.
Create( ) and CreateFromData! ( )
The BAPIs Create() and CreateFromData() create an instance of an SAP business object type, for example, a purchase order. These BAPIs are class methods.
Change( )
The BAPI Change() changes an existing instance of an SAP business object type, for example, a purchase order. The BAPI Change () is an instance method.
Delete( ) and Undelete( ) The BAPI Delete() deletes an instance of an SAP business object type from the database or sets a deletion flag.
The BAPI Undelete() removes a deletion flag. These BAPIs are instance methods.
Cancel ( ) Unlike the BAPI Delete(), the BAPI Cancel() cancels an instance of a business object type. The instance to be cancelled remains in the database and an additional instance is created and this is the one that is actually canceled. The Cancel() BAPI is an instance method.
Add<subobject> ( ) and Remove<subobject> ( ) The BAPI Add<subobject> adds a subobject to an existing object inst! ance and the BAPI and Remove<subobject> removes a subobject from an object instance. These BAPIs are instance methods.
Check these Links out
http://searchsap.techtarget.com/ateQuestionNResponse/0,289625,sid21_cid558752_tax293481,00.html
http://www.sap-img.com/abap/interview-question-on-bapi-rfc-abap-objects-tables.htm
http://www.sap-img.com/fu033.htm
http://www.sap-img.com/abap/ale-bapi.htm
Refer following SDN threads:
Diff. Between BAPI and RFC
Re: BAPI and RFC
difference between RFC and BAPI
Re: Difference Between BAPI and RFC?
Reward all the helpful answers.