Assume we have a data source created from file connection, if a part of data of that data source is in another file we cannot append this new data to existing data source. Also if it is created as new data source we don't have any option to append this data source with existing one. Similarly if the input data set is greater than 75 MB user needs to split it into two data source but cannot append both data source. So, user cannot create a dashboard with his entire data set.
To overcome this problem, need support to append two data sources.