Database Reference
In-Depth Information
SQL Data Sync Framework
The SQL Data Sync framework offers bidirectional data-synchronization capabilities between multiple data
stores, including databases. SQL Data Sync uses the Microsoft Sync Framework, which isn't limited to database
synchronization; you can use the framework to synchronize files over different platforms and networks.
Specifically as it relates to SQL Azure, you can use the Sync framework to provide an offline mode
for your applications by keeping a local database synchronized with a SQL Azure database. And because
the framework can synchronize data with multiple endpoints, you can design a shard, described later, in
which all databases keep their data in sync transparently.
Direct vs. Serviced Connections
You may also consider developing Azure services to keep the database connection to a local network,
and send the data back to the client using SOAP or REST messages. If your Azure services are deployed in
the same region as your SQL Azure databases, the database connection is made from the same
datacenter and performs much faster. However, sending data back to the consumer using SOAP or REST
may not necessarily improve performance; you're now sending back XML instead of raw data packets,
which implies a larger bandwidth footprint. Finally, you may consider writing stored procedures to keep
some of the business logic as close to the data as possible.
Figure 2-2 shows the two different ways an application can retrieve data stored in a SQL Azure
database. A direct connection can be established to the database from the application, in which case the
application issues T-SQL statements to retrieve data. A serviced connection can be made by creating and
deploying custom SOAP or REST services on Windows Azure, which in turn communicate to the
database. In this case, the application requests data through web services deployed in Azure.
Figure 2-2. Data connection options
