Hello,
as I try to understand some of the concepts of SAP HANA I thought it is a good idea to have a look at the internal attributes. I saw that in M_CS_ALL_COLUMNS all columns are listed. When I made a GROUP BY on INTERNAL_ATTRIBUTE_TYPE with a count(*) I found values for NULL, ROWID, TREX_UDIV, TREX_EXTERNAL_KEY and CONCAT_ATTRIBUTE.
As I could read in several sources all of these values are clear to me:
NULL - it is no internal column
ROWID - Internal unique identifyer of the row
TREX_UDIV - some internal transaction value
TREX_EXTERNAL_KEY - multicolumn primary key index
CONCAT_ATTRIBUTE - Index for multicolumns joins
The problem is that I found another INTERNAL_ATTRIBUTE_TYPE called "UNKNOWN" used in _SYS_REPO and SAPSR1 (BW on HANA). The column names always used following pattern: $_SYS_SHADOW_<COLUMN>$"
Does someone know something about this INTERNAL_COLUMN_TYPE?
Thanks
Patrik