Query Model in Live Framework

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Query Model


The Live Framework supports a query model that enables the callers to perform relational queries over HTTP GET. This model is identical for all Live Framework Services and is a part of AtomPub (Microsoft-specific) extensions. In addition to the basic query functionality, the Live Framework libraries extend the query model to support LINQ queries.

The advantages of this query model include the following:

    * Query processing is done on the server and not in the client code.
    * The amount of data sent to the server and received from the server is greatly reduced.
    * LINQ queries can replace many lines of regular code.

The Live Framework libraries enable LINQ queries in any language supported by the Microsoft .NET Framework. These libraries translate the queries to the query string of a GET request on the wire. More importantly, the URI query string produced by this model is consistent, regardless of the underlying service.

All versions of the query model support filter queries, which are base queries that include clauses. These clauses reduce the result set to objects that match the supplied filter. You can also create queries containing composition criteria similar to orderby clauses in SQL, and the composition criteria modify the output of the query. Non-LINQ queries are also available for both HTTP and managed .NET languages, such as C#.

Because the cloud runtime does not have a backing store, it does not support querying over an arbitrarily large dataset. If the number of a query result is too large, the cloud runtime returns just a page of results.

Source : MSDN