SQL CLR

Report
SQL Server 2008 for Developers
UTS Short Course
Course Website

Course Timetable & Materials


http://www.ssw.com.au/ssw/Events/2010UTSSQL/
Resources

http://sharepoint.ssw.com.au/Training/UTSSQL/
Course Overview
Session Date
Time
Topic
1
Tuesday
06-03-2012
18:00 - 21:00
SQL Server 2008 Management Studio
2
Tuesday
13-03-2012
18:00 - 21:00
T-SQL Enhancements
3
Tuesday
20-03-2012
18:00 - 21:00
High Availability
4
Tuesday
27-03-2012
18:00 - 21:00
CLR Integration
5
Tuesday
03-04-2012
18:00 - 21:00
Full-Text Search
What we did last week
High availability

?

What can go wrong? What can we do?

Implementing Database Snapshots

Configuring a Database Mirror

Partitioned Tables

SQL Agent Proxies

Performing Online Index Operations

Mirrored Backups
SQL CLR Integration
Agenda - CLR Integration

What is .NET?

What is CLR Integration?

Requirements on SQL box

Samples

Internals

CLR Integration: Pros

CLR Integration: Cons

Real world - When to use CLR Integration
What is .NET?

An application development platform from Microsoft

Tools, Languages, Runtime (Virtual machine), IDE, …

Rapidly develop secure and robust software

Web and Windows

Full support for object-oriented programming
.NET Overview

IL = Intermediate
Language

CLR = Runtime

CLR




Common
Language
Runtime
= Virtual machine
.NET Framework

Evolution

The whole .NET FX

http://shrinkster.com/1515
(PDF Poster)
What is CLR Integration?

Lets you write your database queries using .NET

Create and debug using VS 2008 IDE

Brand new in SQL 2005 (Standard and Express)

Support for large UDT (User defined types) in SQL 2008 (up to 2GB)

Support for multiple inputs on UDA (User defined aggregators)


e.g. string concatenator that takes in a column and separator char
Any .NET language (C#, VB, C++)
SQL CLR Project
CLR Integration

You can do the same thing as SQL Server using .NET code

Stored Procedures

Triggers

User-defined functions

User-defined types

Aggregate functions
Server - Enabling CLR Integration

Enabled on an instance (not per database)

SQL Script

Execute sp_configure ‘clr enabled’, ‘1’

reconfigure
Stored Procedures
Sample
public partial class StoredProcedures
{
[Microsoft.SqlServer.Server.SqlProcedure]
public static void HelloWorld()
{
// Put your code here
using (SqlConnection cn = new SqlConnection("Context Connection=true"))
{
cn.Open();
SqlCommand cmd = new SqlCommand("SELECT * FROM DEMO", cn);
SqlContext.Pipe.Send(cmd.ExecuteReader());
}
}
What you do
1.
Enable CLR
2.
Create a new database project in Visual Studio
3.
Create a new stored procedure in Visual Studio
4.
Connect to current context using “Context Connection=true”
5.
Add a simple SELECT statement
6.
Deploy and run it
Internals
Assembly collated as set of files



Stored within SQL Server system tables
Assembly, references, program database (pdb), source files
Deployed to SQL Server



Manually
• Catalogued with CREATE ASSEMBLY
• Dropped with DROP ASSEMBLY
Automatically
• Deployed from VS 2008
Security Levels

Safe (default)

Access only to CLR code. No access is allowed to external
resources, thread management, unsafe code or interop.

External_Access

Access is allowed to external systems, such as the
EventLog, File System, and network. Still no access to
unsafe code or interop code.

Unsafe

Access is not limited whatsoever. User-defined types
Custom CLR Functions
Sample
public partial class UserDefinedFunctions
{
[Microsoft.SqlServer.Server.SqlFunction]
public static bool IsValidPostCode(string postcode)
{
return System.Text.RegularExpressions.Regex.IsMatch(
postcode, ^(((2|8|9)\d{2})|((02|08|09)\d{2})|([1-9]\d{3}))$");
}
};
What you do
1.
Create IsValidPostCode in C# (.NET)
2.
Deploy it to SQL Server
3.
Run it
Stored procedure vs. Function

What is the difference?

Function



Base functionality
Independent of Database itself
Stored procedure


Many operations at once
Normally database specific
Triggers
Sample
public partial class Triggers
{
[Microsoft.SqlServer.Server.SqlTrigger(Name = "EmailTrigger", Target = "Customers", Event = "FOR UPDATE")]
public static void SalaryFraudTrigger()
{
SqlTriggerContext context = SqlContext.TriggerContext;
using (SqlConnectioncnn = new SqlConnection("context connection=true"))
{
cnn.Open();
SqlCommand command = cnn.CreateCommand();
command.CommandText = "SELECT * FROM inserted";
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
for (intcolumnNumber = 0; columnNumber<context.ColumnCount; columnNumber++)
{
SqlContext.Pipe.Send(string.Format("Col: {0} = {1}", columnNumber,
reader[columnNumber].ToString()));
}
};
reader.Close();
}
}
}
What you do
1.
Create EmailTrigger in C# (.NET)
2.
Deploy it to SQL Server
3.
Test it
CLR Integration: Pros
(Continued)

Take advantage of the powerful .NET Framework

.NET is a full-featured programming language



Supports things like “for each” loops, arrays, collections
Object Oriented programming model to organise your
queries
Obtaining data from external resources
•
•
•
•
The File System
The Event Log
A Web Service
The Registry
CLR Integration: Pros
For complex calculations


Parsing strings (like the regular expression code)

User-defined types
• Date, time, currency, and extended numeric types
• Geospatial applications
• Encoded or encrypted data (see books online)
User-defined aggregates



Powerful Intellisense and debugging
Generally faster

E.g. CLR aggregate 100x faster than cursor
CLR Integration: Cons
(Continued)

NON MAINSTREAM

Lots of programming for simple operations

Some overhead in communicating with assemblies

Remember – T-SQL is designed and optimised for data, use it!

Not useful if your guys do not know any .NET

Potentially costly to rewrite logic

Companies (including us) have invested a lot in T-SQL
CLR Integration: Cons
There are some restrictions to observe when calling
between T-SQL and SQL-CLR.




You must only use T-SQL supported data types (No
streams)
You can't use inheritance or polymorphism
.NET cannot easily represent either VARCHAR or
TIMESTAMP
•

.NET strings are Unicode, the equivalent of NVARCHAR
The CLR decimal type is not the same as SQL_DECIMAL
When to use CLR Integration

Do I need to manipulate data before it is displayed?


Do I need to do set-based operations such as pivoting?


.NET code and SQLCLR
Are my developers SQL gurus but .NET newbies?


T-SQL
Do I need to do extensive computation or custom algorithms?


.NET code and SQLCLR
T-SQL
Do I have loads of stored procs that are becoming hard to manage?

.NET code and SQLCLR
CLR Integration
The Bottom Line
•
Use T-SQL for all data
operations
•
Use CLR assemblies for any
complex calculations and
transformations
Quick tips

SQL Management Studio Shortcuts

Ctrl + L – Display query execution plan

F5 – Run/Show result grid

Rules for SQL Server
http://www.ssw.com.au/SSW/Standards/default.aspx

SQL Server Cheat sheet
http://www.pinaldave.com/sql-download/SQLServerCheatSheet.pdf
http://www.addedbytes.com/cheat-sheets/sql-server-cheat-sheet/
Session 4 Lab

CLR Integration
Download from Course Materials Site (to copy/paste scripts) or
type manually:
http://tinyurl.com/utssql2009
3 things…

[email protected]

http://ericphan.info

twitter.com/ericphan
3 things…

[email protected]

http://blog.ozdemir.id.au

twitter.com/mozdemir_au
Thank You!
Gateway Court Suite 10
81 - 91 Military Road
Neutral Bay, Sydney NSW 2089
AUSTRALIA
ABN: 21 069 371 900
Phone: + 61 2 9953 3000
Fax: + 61 2 9953 3105
[email protected]
www.ssw.com.au

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