Databases Reference
In-Depth Information
INNER JOIN StoreLocations S ON P.storeid = S.storeid
WHERE S.zipcode = '33498' )
FEDERATED ON (PurchaseHistory)
// Executes a stored procedure across all federation members and returns all the records
SELECT * USING (EXEC GetPurchasesByZipCode '33498' ) FEDERATED ON (PurchaseHistory)
// Performs a JOIN across the same federation to exclude certain records
SELECT * USING (SELECT * FROM CustomerVisits) FEDERATED ON (CustomerVisits)
WHERE storeid IN (SELECT DISTINCT storeid FROM Purchases WHERE amount >= 100)
FEDERATED ON (PurchaseHistory)
The library offers additional features, like caching, sorting, and filtering records based on atomic unit values.
Because it's an open source project, you are welcome to dissect the code and implement your own version of the
library for your own needs.
■
To learn more about the Enzo sharding library, visit
http://enzosqlshard.codeplex.com
.
You will be able to
download the open-source library and a sample application to get you started.
Note
Summary
SQL Database offers a unique feature, called Federations, that promises elasticity at the database layer, giving
you the option to scale your database tier quickly and efficiently. While the first release of this feature has a few
limitations it is clear that many developers will be compelled to evaluate this feature and possibly adopt it to address
their scalability needs.
