DataSource &1 has no key fields; refer to long text for more information

What causes this issue?

DataSource &V1& has no key fields. To generate a data flow, however, it
must have key fields. This is given in the following cases:
A DataSource for transaction data is selected for the generation. A
DataStore object or a HybridProvider is selected as InfoProvider type.
A DataSource is selected for attributes or texts.

System Response

The generation cannot be executed.

How to fix this error?

Specify the key fields of DataSource &V1& using the DataSource
maintenance or define the key from the configuration of the DataSource
fields on the 'Field Assignment' tab.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.