BAPI stands for Business Application Programming Interface.
   
There are 5 different steps in BAPI.
- Create BAPI Structure  
- Create BAPI Function Module or API Method.  
- Create BAPI object  
- Release BAPI Function Module.  
- Release BAPI object.
   
Step1. Creating BAPI Structure:  
- Go to <SE11>. 
- Select Data Type & Enter a name. 
- Click on Create.
- Note: Always BAPI should be in a development class with request number (Not Local Object).
- Select Structure & hit ENTER.
- Enter the fields from your database. Make sure that the first field is the Primary Key Field.
- Then SAVE & ACTIVATE.
   
Step 2. Creating BAPI module: 
- Enter TR.CODE <SE37>.
- Before entering any thing, from the present screen that you are in, select the menu
   Goto -> Function Groups -> Create Group.
   Enter a name (Note: This name Must start with ZBAPI)
   Let this screen be as it is and open another window and there, enter TR.CODE <SE80).
   Click on the Third ICON that says Inactive Objects. 
   Select the group that you just created and click on Activate. 
   Notice that the group you created will disappear from the list of inactive objects.
- Go back to <SE37> screen and enter a name and hit <ENTER>. Then enter the group name that you just created and activated.
NOTE: When you release a function module the respective group will be attached to that particular application. It cannot be used for any other application. NEVER include an already existing group that is attached to another module.
   
Now click on the first Tab that says [ATTRIBUTES] and select the radio button that says remote-enabled module since we will be accessing this from any external system.
  
Then click on the second tab that says [IMPORT].
   
Enter a PARAMETER NAME, TYPE and the structure you created in the first step. Also select the check box ‘Pa’. All remotely enabled functional modules MUST be Pa enabled, where Pa means ‘Passed by Value’ and if you don’t select ‘Pa’, then that means it will be passed by reference..
   
Then click on tab that says [EXPORT].
  
Enter the following as is in the first three fields 
   
  RETURN        TYPE        BAPIRETURN (These 3 field values are always same)
  Here also select ‘Pa’ meaning Pass by value.
   
Note: BAPIRETURN contains structure with message fields.

Then SAVE and ACTIVATE.
   
Step 3. Creating BAPI object: 
- Enter Tr.Code <SWO1>   (Note. It is letter ‘O’ and not Zero).
- Enter a name and then click on create. Enter details. 
NOTE: Make sure that that Object Type and Program name are SAME.   
- Enter Application ‘M’, if you are using standard table Mara. If you are using your own database then select ‘Z’ at the bottom. 
- Then hit <ENTER>. 
- Now we have to add ‘Methods’. High light METHODS and then select the following from the menu: 
Goto Utilities -> API Methods -> Add Methods.
- Enter function Module name and hit <ENTER>.
- Select the second FORWARD ARROW button (>)to go to next step. 
- Check if every thing looks ok and again click on FORWARD ARROW button (>).
- Then select ‘YES’ and click on <SAVE>.
-  Now on a different screen goto TR.CODE <SE37>.  Enter Function Module name and select from the top menu  Function Module -> Release -> Release.
- Goback to TR.CODE <SWO1>.
   
Here select the menu combination shown below in the same order.
- Edit -> Change Release Status -> Object Type Component -> To Implemented.
- Edit -> Change Release Status -> Object Type Component -> To Released.
- Edit -> Change Release Status -> Object Type -> To Implemented.
- Edit -> Change Release Status -> Object Type -> To Released.
- Then click on <SAVE>.
- Then click on Generate Button (4th button from left hand side looks like spinning wheel).
- Then Click on the button that says ‘PROGRAM’ to see the source code.
   
To check if this is present in work flow goto TR.CODE <BAPI>. 
Here it shows business object repository.
- First click on the middle button and then select “ALL” and hit ENTER.
- Goto tab [ALPHABETICAL] and look for the object that you created. This shows that the BAPI object has been created successfully.

Tips by : Ram 

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