.NET Database Programmability and

Extensibilityin Microsoft SQL Server

José A. Blakeley, Mat Henaire, Christian Kleinerman, Isaac Kunen,

Adam Prout, Vineet Rao

Introduction

• Authors are all Microsoft employees• This paper is part 2 of a series of papers

o  1st paper described the architecture and design principles of the integration of the CLR in SQL Server

o This paper is going to present newer aspects using SQL Server 2008

• Topicso User-defined Types/Functionso CLR integration with SQL Server 2008o LINQ with .NETo Performance results

.NET & SQL Server• The Microsoft .NET Framework is a software technology that is

available with several Microsoft Windows operating systems• Microsoft SQL Server is a relational database management system

(RDBMS) produced by Microsoft. Its primary query languages are MS-SQL and T-SQL.

• Common Language Runtime = Java Virtual Machine

...from terabytes to petabytes andexabytes• Data volumes are:

o EXPLODINGo HEAVY

• Why move something heavy?

Basic Concepts

The ability to run application code inside the database in areliable, secure, scalable, and efficient manner adds significantflexibility to the design of applications

SQL Server acts as the operating system for the CLR when it is hosted inside the SQL Server process

User-Defined Functions (UDFs)

CLR user-defined functions (UDFs) provide a mechanism forextending SQL Server with new scalar and table-valued routines written in .NET languages

T-SQL UDFs vs. CLR UDFs:1.T-SQL is more constraining• T-SQL interperated vs. CLR compiled• T-SQL prevents multi-threading

Tabled-Value Functions (TVFs)

CLR TVFs provide a mechanism forconverting raw data (e.g., in a text/binary file or on the network) into a relation. 

User-Defined Types (UDTs)

SQL Server 2005 introduced user-defined types (UDTs) as amechanism to extend the scalar type system of SQL

UDTs allow users to define a type using the .NET framework, and to deploy and use these types within the database

Since CLR UDTs are simply CLR classes with some additional restrictions, they can be instantiated on a managed client as well as in the server

See Example 4.9

User-Defined Aggregates (UDAs)

CLR user-defined aggregates (UDAs) give users the ability to write their own aggregates to suite their own specific needs. 

An example aggregate for calculating population covariance (a measure of how two sets of data vary together) is shown to highlight the different parts of the UDA contract

The contract consists of four methods: • Init(),• Accumulate(),• Merge()• Terminate()

Data Access In Routines

Microsoft has recently introduced new Language Integrated Query (LINQ) technologies that extend .NET languages natively with query expressions to further reduce, and for some scenarios completely eliminate, the impedance mismatch for applications.

An Example

 

Questions?