SAP Enhancement points - Changing standard SAP code using the implict and explicit enhamcement points
Enhancement points are basically hooks at certain defined points within the ABAP code i.e. at the beginning and end of a FORM. These hooks allow you to attach your own custom code which will be executed as if it had been hard coded into the code using a modification. Unlike hard coded modifications these will not be lost during upgrade or patching exercises.
There are 2 types of enhancements with the enhancement framework:
1. Explicit enhancement points: These are basically hooks already coded into the program by SAP at various points of the code. See program RIAUFMVK for examples of these! These are very easy to implement simply go into enhancement mode of SE80 and right click on the enhancement point where you want to add your code and choose 'Enhancement Implementation->Create' Give it a name, description and assign it to a change request (should not be a Z package) and then simply add the code as normal.
2. Implicit enhancement points: These are basically points within ABAP code where an enhancement point is implied, and in which case can be created. Examples of implicit enhancement points are at the beginning and end of FORM's, at the end of a program, include or function module etc. Click here for demonstration of how to implement an implicit enhancement point!