Attunity’s Microsoft SQL Server CDC solution is based on the MS SQL database’s Transaction Logs (TLOG). TLOG records are identified by a Log Sequence Number (LSN). The LSN is used by Attunity’s Microsoft SQL Server CDC agent to identify log stream records.
When logging an UPDATE operation, the MS SQL Server records only changed data to the TLOG. This is not enough information for the CDC agent to provide before and after images for UPDATE statements. There is not enough information to provide the values for changed columns with primary keys, which is the minimum requirement for a CDC agent.
To solve this problem, you must turn Replication on in the MS SQL Server. This replaces the UPDATE changes entered in the log with DELETE/INSERT pairs. This provides enough information for the CDC agent to provide the required data for 1-2 Attunity Integration Suite Service Manual tables. Replication is valid only for tables with primary keys. Therefore, the MS SQL Server CDC Agent works only with tables that have a primary key.
The Replication solution used by Attunity’s MS SQL Server CDC must be enabled by a qualified system administrator. The system administrator must use the tools provided with the MS SQL Server to enable replication.