You can specify a custom key when the table or view has no built-in key or when the existing key is not suitable for data compare.
The following rules apply to custom keys:
- A custom key can be defined under the xml element
<LeftObject>or<RightObject>of the<Pair>element - A custom key must have a name and one or more columns
- The columns that participate in the custom key should exist in the parent table or view
- The key must be defined for each object in the pair of entities.
- The columns that participate in the custom key must be identical for both objects in the specified pair.
The following xml fragment defines a custom key for the pair of table HR.EMPLOYEES:
<TablePairs>
<Pair>
<LeftObject Name="HR.EMPLOYEES">
<Key Name="Custom_Key">
<Column>EMPLOYEE_ID</Column>
</Key>
</LeftObject>
<RightObject Name="HR_COPY.EMPLOYEES">
<Key Name="Custom_Key">
<Column>EMPLOYEE_ID</Column>
</Key>
</RightObject>
</Pair>
</TablePairs>