BAPIs for Budget Control System 
A Business Application Programming Interface (BAPI) is a standardized programming interface that facilitates external access to business processes and data in the SAP System.
BAPIs are defined in the Business Object Repository (BOR) as methods of SAP business objects or SAP interface types.
The BAPIs are implemented and stored as RFC-enabled function modules in the Function Builder of the ABAP Workbench.
See Features below for detailed information on BAPIs in BCS.
You must have installed the Budget Control System in order to use BCS BAPIs.
In the Budget Control System, BAPIs have been developed in the areas of entry documents and totals data . The relevant BAPI scenarios offered in the Budget Control System are:
Create a budget entry document (method BudgetEntryDocFM.Create ):
Using this BAPI, you can create pre-posted and posted documents, but not held documents.
Get detailed information on a budget entry document (method BudgetEntryDocFM.GetDetail ):
You can access an individual effective (posted, preposted, undone) document.
Get a list of FM entry documents (method BudgetEntryDocFM.GetList ):
This method retrieves effective documents according to your selection criteria.
Reverse an FM entry document (method BudgetEntryDocFM.Reverse ):
This method creates a new document which reverses the one specified in the BAPI interface.
Mass process for entering budget data (method BudgetFM.Update ):
You can use this BAPI to import the results of the budget preparation phase to the SAP System, since budget preparation work is often done in another system.
Mass process for reading budget data (method BudgetFM.GetTotals ):
You can use this BAPI, for example, to initialize data for budget preparation with the budget data of the previous year.
Call Transaction BAPI and navigate to the menu area
Access the BAPIs you want to work with. Under the tabstrips Detail, Documentation and Tools , you can find further information about BCS BAPIs.
If you need help in working with BAPIs, call the BAPI Explorer Help under the menu