how to create our own bapi?

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.

http://help.sap.com/saphelp_nw2004s/helpdata/en/7e/5e114a4a1611d1894c0000e829fbbd/frameset.htm

http://www.sapgenie.com/abap/bapi/example.htm

http://help.sap.com/saphelp_46c/helpdata/en/9b/417f07ee2211d1ad14080009b0fb56/frameset.htm

http://searchsap.techtarget.com/originalContent/0,289142,sid21_gci948835,00.html

http://techrepublic.com.com/5100-6329-1051160.html#

http://www.sap-img.com/bapi.htm

http://www.sap-img.com/abap/bapi-conventions.htm

http://www.sappoint.com/abap/bapiintro.pdf

http://www.sapgenie.com/abap/bapi/example.htm

http://help.sap.com/printdocu/core/Print46c/en/data/pdf/BCMIDAPII/CABFAAPIINTRO.pdf

http://help.sap.com/printdocu/core/Print46c/en/data/pdf/CABFABAPIREF/CABFABAPIPG.pdf

http://help.sap.com/printdocu/core/Print46c/en/data/pdf/BCFESDE8/BCFESDE8.pdf