When you export an RDBMS source configuration from an IWX v4.2 environment and import it into another IWX v4.2 environment, the import will be successful but the Table Groups tab and the table(s) under it will not be displayed in the target IWX environment.
This is a limitation in IWX v4.x which will be addressed in future releases.
a) As a workaround create a dummy table group with a table and click the ingest option.
b) After performing the above step, the imported Table Group(s) from the source and also the newly created dummy table group will be displayed.
Applicable Infoworks versions: