Replication of Tables Without Unique Keys

With certain limitations, Replication Server supports the replication of a table to Adaptive Server even if the table does not have a unique key.

If a table does not have a unique key, it is possible that there are two or more rows with the same values. However, DSI shuts down if it cannot find a unique row to apply an operation. The dsi_top1_enable parameter instructs DSI to select and update only the first instance of multiple similar rows by setting unsigned_integer to 1 in the top unsigned_integer clause of the Adaptive Server select statement.

Set the dsi_top1_enable parameter to on to support replication of tables without unique keys. To set the parameter for:

A specific connection to a replicate Adaptive Server database, enter:
```
alter connection to data_server.database set dsi_top1_enable to {on | off}
```
All replicate database connections to the Replication Server, enter:
```
configure replication server set dsi_top1_enable to {on | off}
```

The default is off.

Do not use configure replication server to set dsi_top1_enable to on if there are connections to non-Adaptive Server replicate databases. Instead, use alter connection to set the parameter individually for each Adaptive Server replicate database connection.

During replication from supported databases into SAP HANA database, Replication Server supports the replication of LOB columns in a table without unique a key. See Replication of LOB Columns in a Table Without a Unique Key in the Heterogeneous Replication Guide.

Limitations

Replication Server does not support replication of a table without unique keys if:

There is a Java object datatype in the table. See Java Datatypes in theReplication Server Reference Manual.
There is a customized function string for the table.
There is a table replication definition for the table.
Transactions use updates and deletes with the like option in the where clause at the primary database.
The replicate database is not Adaptive Server.