BDC

                   BDC ( Batch Data Communication ) is used for uploading mass data into SAP system. In SAP system BDC also referred to batch input or data transfer.

                 Data input entered by user simulated in BDC by data packet. The transaction then started using this internal table as the input and executed in the background.

To Perform BDC Following Methods Are use:
                               Call Transaction Method 
It is the process of transferring the data from flat file into SAP by calling a transaction through a series of sequence of steps.

Properties of call transaction method .

• This method is used for transferring less amount of data(<10,000 records).
• This method uses Synchronous and Asynchronous updates.
•  Processing is faster.
• We need to handle the errors and the success messages by declaring an internal table of type BDCMSGCOLL.
• Data is updated automatically.

FUNCTION MODULES :

1. F4_FILENAME ( Open the legacy file [.txt or .xls]) .

2. TEXT_CONVERT_XSL_TO_SAP ( Convert the .xls file to sap format) : Using 
    for only .xls files.
3. GUI_UPLOAD : Using for only .txt files.

MODE:

It specifies the type of the mode to execute the transaction.

There are 3 options for mode

• A All screen mode(Foreground).
• E Error screen mode (only error screens will be displayed).
• N No screen mode (Background).

                                         Session Method.

Properties of call session method .

• This method is used For transferring small amount of data .
• This method uses Synchronous Updates.
• Processing is Slower
• Error log Is Created.
• Data is not updated until session is processed.

Function modules :

1. F4_FILENAME ( Open the legacy file [.txt or .xls]) .

2. TEXT_CONVERT_XSL_TO_SAP ( Convert the .xls file to sap format) : Using 
    for only .xls files.
3. GUI_UPLOAD : Using for only .txt files.

Data packet is an internal table has a structure of BDCDATA, it has fields:

1. PROGRAM (program name)

2. DYNPRO (screen number)

3. DYNBEGIN (New screen start) X=new screen

4. FNAM (Field name)

5. FVAL (Field value)

RECORDING METHOD:

Since, it is very difficult to find technical information of each field on the screen, we go for a method called as "Recording method"

The recording method is going to record all the fields in the transaction and it generated the technical information such as program name, screen no, field name, field value for each field on the SAP screen

By using the recording method, it is very easy to create a BDC program.