[This document supports a preliminary release of a software product
that may be changed substantially prior to final commercial release.
This document is provided for informational purposes only.]
SQL Data Services (SDS) is the relational database offering for the
Azure Services Platform. SDS exposes these relational capabilities
through the existing network protocol, Tabular Data Stream (TDS). TDS
is the underlying protocol used by all SQL Server client libraries such
as ADO.NET, ODBC and all other third party and open source access
libraries.
The use of the existing protocol enables the service to extend the
SQL data platform to the cloud while maintaining symmetry with the
existing SQL Server applications models.
SDS offers friction-free provisioning allowing customers to create
databases without having to worry about hardware and software
procurement, setup or maintenance. SDS also ensures high availability
and fault tolerance. The pay as you grow model provides unlimited scale
at low cost.
TDS access to the database services allows customer applications to
communicate with the service using existing client libraries (such as
ADO.NET, ODBC or JDBC).
Customers can optionally host their applications in Azure Compute as shown in the following illustration.
The exposure of the TDS protocol provides a programming model in the
cloud that is similar to the on-premise database programming
experience. Customers can easily migrate their applications from
on-premises databases into the cloud as the SQL surface area is largely
unchanged.
The database service exposes the strength of SQL Server, the power
of Transact-SQL and related richness of the existing SQL tools to
customers. Application developers can leverage their existing knowledge
when working with the service.
The Azure hosting services complement SDS allowing applications to
be hosted close to the database where the application data is stored
thereby reducing the overall cost of communicating with the service
while at the same time providing lower operational expenses.
High Level Architecture
As shown in the high level architecture diagram, TDS access to the
database services allows customer applications to communicate with the
service using existing client libraries (such as ADO.NET, ODBC or
JDBC). SQL Data Services provides:
- Provisioning service for on boarding new customers within the Azure platform.
- Billing,
metering and rollup functionality for users to discover service usage
information. This metrics information is also used for customer billing.
- Concepts
of Server and User Database which provides context for the management
of the databases in the cloud. SDS maps these logical concepts to the
underlying platform.
Migrating from ACE to the Relational Model
The
relational model described in this topic replaces the SDS ACE
(Authority, Container and Entity) model. The current SDS CTP
participants have the following options:
- Migrate existing applications to use the SDS relational
service. Customers can optionally host their applications in Azure
Compute.
- Use Windows Azure Storage for applications that don’t need relational capabilities
The SDS ACE model, with SOAP and REST interfaces, is being phased out.