To maintain the integrity of CDC tables some operations on these tables are not allowed by users. The following table provides details.
Table 4. Operations allowed on Change Tables and Change Tracking Tables
Operation
Change Table
Change Tracking Table
Read
Allowed
Allowed
Delete
Allowed
Allowed
Create
NOT allowed
NOT allowed
Update
NOT allowed
Allowed on _User-Misc field
NOT allowed on any other field
You can read and delete records, provided they have the proper authorization. For example, it is a common process for an ETL application to read records to copy them to an external data source, or a DBA may delete change table and change tracking table data when it is no longer needed. However, you are not allowed to create records in these tables, and with one exception they are not allowed to update records.
The process of capturing the data is handled by an internal OpenEdge RDBMS trigger. The creation of the records is exclusively in the domain of the internal CDC database triggers.
Users are allowed to update just one field in the Change Tracking Table record. Only the _User-Misc field can be modified. This field is available to allow runtime customization by applications that consume the CDC data. For example adding data to this field to indicate that a record has been read or that it can be deleted.
