How to get/follow/investigate an XPath to get an attribute or to search for attributes#

Example:

CALL METHOD me->get_xpath_property_as_string
  EXPORTING
    ir_entity       = lr_btadminh
    iv_xpath        = '/BTOrderHeader/BTHeaderPartnerSet/BTPartnerAll/PARTNER_NO'
    iv_filter_value = 'YSSC001'
    iv_filter_attr  = 'PARTNER_FCT'
  IMPORTING
    ev_value        = lv_bupa    	

1. Set external breakpoint to the method above
2. Execute method
3. At the break put "lr_btadminh" into the "Data Explorer" tab
4. Follow tree as described:

a) BTOrderHeader

> CONTAINER_PROXY > DATA_REF > RELATIONS(x).RELATION_NAME=BTOrderHeader

Search in all x items for RELATION_NAME=BTOrderHeader and choose that item.
From that item drill down as in b)

b) BTHeaderPartnerSet

> OBJECTS[1] > DATA_REF > RELATIONS(x).RELATION_NAME = BTHeaderPartnerSet

c) BTPartnerAll

> OBJECTS[1] > DATA_REF > RELATIONS(x).RELATION_NAME = BTPartnerAll 

d) PARTNER_NO (last part is the attribute)

> OBJECTS(x)

Search in all object for

> DATA_REF > ATTRIBUTE_REF.<iv_filter_attr> = <iv_filter_value>

take that object and take

> DATA_REF > ATTRIBUTE_REF.PARTNER_NO

Then you get the value of that attribute (business partner) into lv_bupa.