Adapter Object: CUSTOMER_REL有两个功能：
- 同步Contact Person，以Relationship的方式
- 同步Partner Function，同样以Relationship的方式
- Distribution of Partner Functions from SAP ECC into CRM
- Distribution of Partner Functions from CRM into SAP ECC
针对self-reflection，其实在Define Partner Functions中Block选项就是干这个的，如果不勾选的话，意味着在Partner Determination过程中，可选自身作为任意的Partner Function。详见Note: 417022
在CRM中，self-reflection用BP Role来体现。但是CRM中，BP Role没有什么特殊功能，只是UI的集合，参见Note: 596334
The self reflexive partner function by design are not replicated to CRM
from R/3, because in the CRM system they do not make sense as per the
design and data model of the CRM system.
In R/3 when a customer is created in a particular sales area under a
particular account group self reflexive partner functions like
Ship-to-party, Bill-to-party and so on are added.
This information is represented in CRM in terms of roles because in CRM
partner functions refer only to the ones that a BP has with another BP
and not itself. All the information related to a BP in CRM are stored
in the BP data itself and never through partner functions.
Similarly, these partner functions will not be displayed in the
[RELATIONSHIPS] tab. Please note that self-reflecting partner
functions are not allowed in CRM because it’s physically not possible
for a Business Partner to have a relationship or a partner function
with himself. Such partner functions are subject of partner
determination process in CRM, and by default Ship-to-party, Payer and
Bill-to-Party functions are assumed for all Business Partners.
During data exchange such Partner Functions are simply ignored.