Akvelon has built a highly-configurable global search add-in for CRM and in this video Sergei shows a demo of their search product working with Dynamics CRM 2011. Akvelon's Global Search supports searching data across multiple entities, contents of attachment, displays related entities for many-to-many (N:N)relationships and searching by lookup fields. It also has the ability to search custom entities and fields which will come in very handy for xRM implementations. Behind the scenes, the add-in uses a combination of index based search, live queries and cached results.
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