Defining Key Fields (BOR) 
Use BOR objects are always identified using one or more key fields. You specify what key information is required to uniquely identify an object of this type.
You are on the screen Change Object Type <object type> in the Business Object Builder.
Position the cursor on the component name Key Fields (blue background).
Choose
.
Answer YES to the question Create with ABAP Dictionary field proposals?
The Create with Data Dictionary Field Proposals dialog box appears.
Enter the table from which you want to reference the fields, and select the fields that are the key fields of your object type.
Note
Only alphanumeric data types are allowed as key fields. The total length allowed for all key fields of an object type is 70 characters.
Edit the ID and texts of the key field as required. Bear in mind the rules for naming object type components.
Choose
.
For more information, see Data Declaration for Variables Used.