SQL Data Services (SDS), formerly known as SQL Server Data Services (SSDS), are highly scalable, on-demand data storage and query processing utility services. Built on robust SQL Server technologies and Windows Server, SDS provides highly available, secure, standards based web services that are easy to program and provision.

On Monday 10/27/2008, Microsoft announced the latest upgrade of SSDS at the PDC2008 conference in Los Angeles. This announcement to public with a change of name from SSDS to SDS (SQL Data Services).  Bear in mind that the beta participation (public) is only available by invitation and lots of new features for your excitement.

New features in this service upgrade including JOINs, extensions to simplify the query syntax, new functions like OrderBy and Take, integration with .Net Services Access Control Service, and new usage metrics. To get to know the documentation, code samples, and tools from the DevCenter have been updated with information to cover the new features in this upgrade.

 

New features in this upgrade:

Additional Query Support

a) Joins

Join query support in SQL Data Services (SDS) allow you to retrieve entities from a container based on a join condition involving properties on different kinds of entities. For example, if you have a container with customer and order entities, a query to find orders for a given a customer would require you join the customer and order entities based on a common property. Since both the customers and orders are in the same container, you query the same container twice (using aliases); first find the customer and then find orders for that customer using a join condition.

b) OfKind

To simplify the join Syntax, SQL Data Services (SDS) has introduced an OfKind function. This function can be specified on a query From clause to distinguish between multiple entity Kinds within a container.

An example would be

from c in entities.OfKind("Customer") select c

c) Order By

SQL Data Services (SDS) now supports an Order By clause in our query syntax. This optional clause allows you to have your query results returned ordered by one or more properties of your choosing in either ascending or descending orders

d) Take

SQL Data Services (SDS) now supports a Take function in its query language. This new function can be used to restrict the number of entities returned in a given query.

.Net Access Control Integration (SOAP Only)

The .NET Access Control Service is a hosted, secure, standards-based infrastructure for multi-party, federated authentication and rules-driven, claims-based authorization. SQL Data Services (SDS) supports authentication and authorization via tokens issued by the .NET Access Control Service. This allows applications secure not only their own web service layer, but also their SDS-based data layer using the same, declarative access control mechanism.

Other forms of credentials, besides username/password, can be used to obtain a token from the identify provider. They are:

a) X.509 certificate

b) InfoCard

In this release, using token-based authentication scheme with SDS has the following limitations:

a) When communicating with SDS, the token-based security is available only when using the SOAP protocol. For applications using the REST protocol, only the basic authentication is supported (username/password).

b) Requires a .NET Services solution account.

Metrics

Service users often want to know the usage pattern of the service. Microsoft® SQL Data Services (SDS) user may want to find:

a) How many containers or entities do I have?

b) What is the total storage consumed by an authority or a container?

c) What is the amount storage used by blobs in a container?

d) What is the aggregate number of requests (GET, POST, PUT and so on) sent against an authority or a container?

e) What is the number of request and response bytes sent with a specific authority or container in scope?

The service provides this information as properties on authorities and containers.

For more detail, please visit the SDS DevCenter at http://msdn.microsoft.com/en-us/sqlserver/dataservices/default.aspx