Fetching feature layer related data from MySQL or a separate DB on map's info window

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Silverlight

mapping

Situation is:
a). I am having one feature layer which had been plotted on a base map say polygonal features (blocks of land).
b). Related data (owner names of blocks) in a separate database (like MySQL/ Excel file / Oracle).

What I need:
a). The data from feature layer and from the database can be shown inside the info window popup simultaneously (e.g. block name from feature layer and block owner's name from separate database).
b). The functionality of displaying simultaneous data (from feature layer and database) can be achieved through query related records window. I have seen an example here Query Related Records but unable to get that where the database connection had been made and the datatable or dataset values are fetched from.

Kindly help as I am new to ArcGIS.

P.S.: I am using ArcGIS for Silverlight 10.1