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Source Table
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Change Table (C)
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Change Tracking Table (CT)
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ETL
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Add a field
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No record
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No record
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No action required.
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Add a field policy which is a new field in source table
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New field
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Record written indicating Field Add
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Existing ETL program continues to work. You can use CT record to know if this action occurred and decide to alter ETL.
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Delete field (offline)
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Rename field on Chg Tbl (offline) causes CRC issue on ETL process **
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Record written indicating Field Delete
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Existing ABL ETL will fail with a CRC issue immediately. If SQL ETL references the deleted field name it will fail. There can be dynamic use of the CT record indicating field delete.
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Delete field policy
(Create a new policy without a field), source field still exists
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Field exists with old name
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Record written indicating Field Delete
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ETL can use bitmap to indicate which fields can be extracted.
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Re-add field policy with change field already in Change Table
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Field exists
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Record written indicating Field Add
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Existing ETL program continues to work. You can use CT record to know if this action occurred and decide to alter ETL.
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Add field policy with existing field name in source table
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New field in the change table
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Record written indicating Field Add
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Existing ETL program continues to work. You can use CT record to know if this action occurred and decide to alter ETL.
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Re-add field and field policy with same name as was previously dropped
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New field with the same name added(online)
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Record written indicating Field Add
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Use CT record to know if action occurred
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Rename field on source same as Change field that was deleted with ABL special naming convention
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No action
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Rename field on source that already has a change field
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Field renamed
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Existing ETL will be effected by a CRC change caused by rename.
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