# Limitations and considerations

You should be aware of the following limitations and considerations when using a Teradata source.

The following limitations apply when using a Teradata source with Qlik Talend Cloud Data Integration.

## Change processing limitations

* Replicating data with 4-byte emoji characters is not supported.
* When storing changes in Change Tables, the before-image will not be stored.
* The Start from timestamp run option is not supported.
* If one of the context columns is part of the primary key or unique index, UPDATE and DELETE operations are not supported.
* Context columns cannot be LOB columns.
* DDL operations are not supported when change processing is enabled.
* When inserting a record and then updating the same record, set the task error handling policy so that the No record found for applying an update action is INSERT the missing target record.