ETL Step 3: XREF
In the XREF step, the system generates MD_ENTERPRISE_KEY for records based on the value of MD_BUSINESS_KEY. Unlike many other staging tables that are dropped and re-created every time when the ETL Job runs, *_XREF tables (naming convention: *_XREF) are not cleared. *_XREF tables maintain a mapping relationship between MD_BUSINESS_KEY and MD_ENTERPRISE_KEY to make sure each MD_ENTERPISE_KEY is uniquely mapping to a MD_BUSINESS_KEY.
The system also generates MD_ENTERPRISE_KEY for other reference entities if the referred record is not arrived. This is a part of the Late Arriving Dimension function.
*_SSI tables are input in this step, while *_XREF tables are output.
The following table lists the key staging tables.
Table Name |
Table Description |
---|---|
<TARGET_ENTITY_NAME>_ XREF |
Contains a mapping relationship between MD_BUSINESS_KEY and MD_ENTERPRISE_KEY |
The XREF table contains the following system reserved fields.
Field Name |
Field Description |
---|---|
MD_BATCH_ID |
For late arriving data, the batch ID is set
to |
BUSINESS_KEYVALUE |
Stores business key values that are read from MD_BUSINESS_KEY in the *_SSI tables |
ENTERPRISE_KEY |
Stores generated sequence numbers |