What is the difference between the BU and ZK OK codes in SAP macro

I am trying the po开发者_运维百科st an invoice to SAP using the F-47 transaction and using SHDB to record the transaction and learn how it works. I see there that sometimes BU and ZK BDC OK codes are used. I would like to understand the difference between them, but could not find any official documentation. Please, explain the difference between the two?

I found the meaning of some of the status codes. I post it here, so I can remember:

• /00. Enter
• /AB Go to overview
• =ZK Go to additional information
• =ENTE Enter (don't know exactly what is difference between /00)
• =PI select cursor location
• =STER Go to taxes
• =DELZ delete cursor
• =GO continue
• =BU post (save)
• /EEND end processing
• =Yes select "yes" from message box
• =BP park (save)
• =ENTR Enter (don't know exactly what is difference between =ENTE or /00)
• =AE save when changing document
• =BK change document header (parking or posting parked document)
• =P+ next page
• =BL delete parked document

A BDC_OKCODE indicates which action is (will) be executed on a screen (things like save, back, exit etc). The BU code is used for a SAVE function (like in MM01 transaction). Sorry but I cannot recall to which function ZK maps to. Obviously their difference lies in the fact that they map to different functions. You can still find out which function each button utilizes by using System->Status->GUI status.

By the way, BTCI transactions are not fully robust- minor changes in GUI flow let your program break. Error handling / analysis is tedious.... DId you have a look to posting methods more preferably? E.g. like BAPI_* function modules? With the help of LSMW you can browse for different input methods and use them later standalone. Or you can use transaction BAPI directly.