The following table describes the fields of the _Cdc-Change-Tracking table.

Table 1. _Cdc-Change-Tracking fields
Field Size Description
_Policy-Id char(22) Table Policy Id
_Tran-Id integer Transaction number
_Time-Stamp timestamp tz Timestamp of database trigger execution – UTC with zone
_Change-Sequence int64 Sequence of change within the Object for a policy Id
_Operation integer Value to indicate what type of operation is occurring:
  • 1 — Create
  • 2 — Delete
  • 3 — Before Update
  • 4 — After Update
  • 5 — Field Delete (in Source Table)
  • 6 — Partition Drop
  • 7 — Partition Truncate
  • 8 — Partition Deallocate
  • 9 — MT Partition Deallocate
  • 10 — MT Partition Drop
  • 11 — Merge Partition Drop
  • 12 — Field Add (in Change Table, also specifies re-tracking of a field)
_Source-FieldMap raw(256) ABL/SQL methods are provided to access values in this field.
_Source-Rowid int64 Support for Pro2
_Source-Partition-Id integer Support for TP
_Tenant-Id integer Support for MT
_Version integer Future to support change table record format changes
_User-Misc char x(8) User defined field — possible use to mark it when an operation has occurred that moved a record to the external data source.
_Misc char x(8) Reserved for future use

The following table describes the indexes of the _Cdc-Change-Tracking table.

Table 2. _Cdc-Change-Tracking indexes
Index Name Index Field Attribute
_Sequence-Id 1 _Source-Table-Number (These two fields together point to a single instance of the table)

2 _Change-Sequence

 Unique

Primary
_Time-Stamp-Seq 1 _Source-Table-Number

2 _Time-Stamp

3 _Change-Sequence

Non Unique
_Part-Rec-Id 1 _Source-Table-Number

2 _Partition-Id

3 _Recid

4 _Change-Sequence

 Unique

The CDC Change Tracking Table is a table used by all change record capture activities. The table tracks each CUD (create/update/delete) activity by a change sequence order. This table can be used to drive query activity in the CDC Change Table. The database CDC trigger will write a Change Tracking and Change Table record in most cases when it is executed. Understanding the connection between the two tables is important because data describing the change activity is stored in the Change Tracking Table. When accessing the the data in the Change Table, use the Change Tracking Table to establish record modification sequence and which fields changed in the Source Table.