When you configure a lookup, you define the behavior when a lookup condition returns more than one match. Some types of lookups have restrictions on the multiple match policy.
The following types of lookups have multiple match policy restrictions:
Uncached lookups
Some connector types do not support the multiple match policies
Return first row
and
Return last row
in uncached lookups. If you select either of these policies, and the connector does not support the policy in uncached lookups,
Data Integration
enables the
Lookup Caching Enabled
advanced property, and you cannot edit it.
Lookups that use a dynamic cache
If the Lookup transformation uses a dynamic cache, you must configure the multiple match policy to return an error. Other multiple match policies are not supported.
Salesforce lookups
When you perform a lookup against a Salesforce object, you can return any row or return an error.
Lookups in advanced mode
When you use the Lookup transformation in advanced mode, you can return all rows, return any row, or return an error. The multiple match policies
Return first row
and
Return last row
are not supported.
When you define the behavior for multiple matches in advanced mode to return an error, the Lookup transformation drops duplicate rows and does not include the duplicate rows in the log files.
For more information about the multiple match policies supported by different connectors, see the help for the appropriate connector.