To demonstrate the use of the “BDCDATA” structure, we will work through a “change vendor” example.
Ultimately, we want to perform batch input to change already existing vendor records. Specifically, we will add a street address to each vendor. Before coding a batch input program, you must research the appropriate transaction. This research consists of determining the online program name, screen numbers, and field names for the entire transaction.
In our example, this transaction would be the “Change Vendor” transaction.  The transaction code is “FK02”.

Researching Transaction - 1st Screen

When you come to the first screen of the transaction to research, perform the following steps:
Step 1: Use the “System -> Status” menu path to determine the online program name, the screen number, and, if unknown, the transaction code. In our example, the online program name is “SAPMF02K”, the screen number is “0106”, and the transaction code is “FK02”.
Step 2: In each screen field that you want to fill with data, determine the field name by placing the cursor in the field and pressing the ‘F1’ key. When the ‘Help’ dialogue box pops up, click on the “Technical info” push button. On the ‘Technical Info’ dialogue box, the field labeled “Field description for batch input” will give the appropriate field name.
In our example, we will need to fill the vendor number field with an already existing vendor. This field name is “RF02K-LIFNR”.  We will also have to check the address check box.  This field name is “RF02K-D0110”.
Step 3: Determine how to proceed in the transaction. The “command field” of each screen is used to capture the user’s actions (i.e., clicking on a push button or pressing a function key). The field name for this “command field” is “BDC_OKCODE”.
In our example, we can press the ‘Enter’ key to move on to the next screen. This action does not require a value in the “command field”. We could use a  “/00” value in the “BDC_OKCODE” field, but it is not necessary.

Researching Transaction - 2nd Screen

When you come to the next screen of the transaction, perform the following steps:
Step 1: Use the “System -> Status” menu path to determine the online program name and the screen number. The online program name will not always be the same throughout a transaction. In our example, the online program name is “SAPMF02K” again and the screen number is “0110”.
Step 2: In each screen field that you want to fill with data, determine the field name by placing the cursor in the field and pressing the ‘F1’ key.  When the ‘Help’ dialogue box pops up, click on the “Technical info” pushbutton.  On the ‘Technical Info’ dialogue box, the field labeled “Field description for batch input” will give the appropriate field name. In our example, we will need to fill the street field.  This field name is “LFA1-STRAS”.
Step 3: Determine how to proceed in the transaction. In our example, we want to save the record.  We can click on the ‘Save’ pushbutton or press (CTRL+S) key to save the record.
In the “command field” of a screen, we can use a forward slash (“/”) followed by the function key number to mimic pressing a function key.
In our example, we will use a “=UPDA” in the “command field” to save the record. Remember that this command field is referenced with the “BDC_OKCODE” field name.

BDC Table Contents

At the end of your exercise, you must have the following data.