Alias of the data source in a join view helps you identify data sources that share the same name.
By default, Data Validation Option assigns the data source name as the alias name. If you select a data source with the same name as any other data source in the join view, Data Validation Option appends the alias name with a number.
If you edit alias name after you a create a join view, Data Validation Option deletes the join conditions. Create the join conditions again to save the join view.