SQL Data Services RDBMS Model
[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.