1. SQL Server™ .NET
Programmability
José A. Blakeley
Architect
SQL Server
Background
l Transact SQL (T -SQL)
Ø SQL Server’s database programming language
Ø Includes:
§ SQL DDL, SQL DML
§ Variables, assignment, iteration, procedures, functions
l .NET Platform
Ø .NET runtime (Common Language Runtime)
§ Verifiable Intermediate Language
§ Managed memory – garbage collection
§ Multiple languages (e.g, C#, C++, Cobol)
(e.g ,
Ø Frameworks library (e.g., GUI, Files, XML)
Ø Assemblies – New Dynamic Link Libraries
§ Contain code + metadata (class definitions, assembly
dependencies)
§ Unit of code deployment, security, versioning
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 1

2. Outline
l Motivation
l Basic Infrastructure
Ø Hosting overview
Ø Data access inside process: ADO.NET
Ø SQL types
l SQL features
Ø Server assemblies
Ø Functions, procedures, triggers
Ø Types and aggregates
l Summary
Motivation
l Broaden the set of languages for running
data-
data -intensive business logic in server
Ø IT Developers and ISVs
Ø Multiple languages: Visual Basic ®, C#, C++, J#, …
Ø Same mid - and server -tier data access model
mid- server-
Ø Same tools: IDE, project model, debugging, …
Ø Transact-
Transact-SQL still supported
l Packaged as .NET assemblies
Ø Verifiable, secure
l Deployed to SQL Server as
Ø Functions, procedures, triggers, types
l Basis for SQL Server Extensibility
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 2

3. Development Steps
VB, C#, C++ Build
VS Assembly:
Project “TaxLib.dll”
TaxLib.dll”
Runtime
hosted inside SQL Data Definition:
create assembly …
SQL Server create function …
create procedure …
create trigger …
create type …
SQL Queries: SQL Server
select
sum(tax(sal,state)
sum(tax(sal,state) )
from Emp where county
= ‘King’
Basic Infrastructure
l Hosting common language runtime
inside SQL Server
Ø 4Ss: Safety, security, scalability, speed
Ø Run verified, type-safe code inside
type-
process
Ø Multiple languages
l Data access in process
Ø Based on ADO.NET
Ø Same data access programming model
as middle -tier
middle-
l SQLTypes
Ø SQL type semantics in managed code
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 3

4. Hosting .NET Runtime
l Safety
Ø Prevent user code from corrupting the server
process
§ Verifiable code
Ø Use runtime code permissions to control user code
when calling
§ Unmanaged APIs, user interface, threads, synchronization
l Security
Ø Authorized access to SQL Server data from user
code via SQL Server authorization model
Ø Authorized access to system resources from user
code via runtime code permissions
Ø Administrators control permissions given
to assemblies
Three Code Permission Sets
l SAFE
Ø Execute & data access permission
Ø No access to resources outside SQL Server
Ø No unmanaged calls
Ø Must be verifiable
l EXTERNAL_ACCESS
Ø SAFESQL + access to external resources (Net, File
permissions)
Ø Requires EXTERNAL ACCESS permission to create
Ø SQL Server will impersonate the caller
Ø Must be verifiable
l UNRESTRICTED
Ø No controls: Can call unmanged code, can be un-verifiable
un-
Ø Only Administrators can create
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 4

5. Hosting .NET Runtime
l Scalability
Ø As many concurrent users as, as fast as
Transact-
Transact-SQL
§ Integrated SQL Server and runtime threads
§ Collaboration between SQL Server and GC
§ SQL Server becomes OS to the .NET runtime
l Speed
Ø Efficient data access in process
Ø Compiled user code, not interpreted as
Transact-
Transact-SQL
Ø Fast transitions in/out of runtime
Speed: Functions
.NET function vs. Transact-SQL inline
800
Query time (ms)
600
400
.NET function vs. Transact-SQL function
200 1000000
Query time (ms)
100000
0
1 3 5 7 9 10000
11 1 3 15 17 19 21 23 25 27 29
1000
Integer ops per func call
100
.NET func 10 TSQL inline
1
100 1000 10000
Integer ops per call
.NET functions approximating speed of Transact-
Transact-
SQL inline expressions .NET func TSQL func
.NET framework functions much faster than
Transact-
Transact-SQL functions for complex expressions
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 5

6. Outline
l Motivation
l Basic Infrastructure
Ø Hosting overview
Ø Data access inside process: ADO.NET
Ø SQL types
l SQL features
Ø Server assemblies
Ø Functions, procedures, triggers
Ø Types and aggregates
l Summary
ADO .NET Data Access
Controls,
XSL/T, X -Path,
X- Designers,
Validation, etc etc
XmlData-
XmlData- DataSet
Document Sync
SQL Server
XmlReader XmlReader
Managed
Managed
Managed
XmlText- XmlNode-
XmlText- XmlNode - Provider
Provider XmlText- XmlNode-
XmlText- XmlNode -
Reader Reader
Provider Reader Reader
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 6

7. Data Access Inside SQL
using System.Data.SqlServer;
System.Data.SqlServer;
using System.Data.SqlTypes;
System.Data.SqlTypes;
public class ShippingCosts {
public static SqlMoney FreightByShipper( string ship ) {
FreightByShipper(
SqlCommand cmd = SqlContext.GetCommand( );
SqlContext.GetCommand(
cmd.CommandText = "select sum(o.freight) as freight " +
"from orders o join shippers s on o.shipvia = s.shipperid " +
"where s.companyname = @CompanyName " ;
@CompanyName
SqlParameter param = cmd.Parameters.Add("@CompanyName",
cmd.Parameters.Add("@CompanyName",
SqlDbType.NVarChar,
SqlDbType.NVarChar, COMPANY_NAME_COL_LENGTH);
param.Value = ship;
ship;
SqlMoney amount = cmd.ExecuteScalar( );
cmd.ExecuteScalar(
return amount;
}
}
SQL Types
l Reduce impedance mismatch between
programming language and data
l Consistent expression evaluation in
mid-
mid- and server-tier programming
server-
l SQL Types library
Ø Managed classes: System.Data.SqlTypes
Ø Provide SQL semantics
§ Nullability, three-
Nullability , three-valued logic
§ Precision and scale in operations
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 7

8. SQL Types Example
l Tax function using SQL types
using System;
using System.Data.SQLTypes;
public class myFinances
{
public static SQLDouble tax( SQLDouble sal )
{
if ( sal < 50000.0 ) return sal * 0.15;
0.15;
if ( sal >= 50000.0 && sal <= 90000.0 ) return sal * 0.23
else return sal * 0.35;
0.35;
}
}
SQLDouble makes function NULL-aware
NULL-
Outline
l Motivation
l Basic Infrastructure
Ø Hosting overview
Ø Data access inside process: ADO.NET
Ø SQL types
l SQL features
Ø Server assemblies
Ø Functions, procedures, triggers
Ø Types and aggregates
l Summary
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 8

9. SQL Features
l Assemblies
l Functions
l Procedures
l Triggers
l Types
Creating An Assembly
CREATE ASSEMBLY geom FROM ‘m1typesgeometry.dll’
‘ m1types
WITH PERMISSION_SET = SAFE
WITH AUTOREGISTER
DROP ASSEMBLY lib_geom
l Assemblies stored in database
Ø Backup, restore with data
l Code permissions assigned per assembly
Ø Safe (default), external access, unrestricted
l Autoregister functions
Ø Using .NET custom attributes
l Assembly benefits
Ø Self-
Self-describing metadata: Types, file dependencies
Ø Unit of code deployment: Permissions, versioning
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 9

10. Altering An Assembly
l Cannot invalidate persistent data or indexes
l Implies
Ø No tables with columns of UDT from this assembly
Ø No indexes on functions of this assembly
l Force option allows ALTER even if persistent
dependencies exist
l Packaging considerations
Ø Place routines and types in different assemblies
Creating A Function
CREATE FUNCTION distance (
@x1 int, @y1 int, @x2 int, @y2 int ) RETURNS float
int, int, int,
EXTERNAL NAME ‘geom:CPoint.Distance’
‘geom:CPoint.Distance’
DETERMINISTIC
RETURNS NULL ON NULL INPUT
DROP FUNCTION distance
l Functions called from queries
Ø Can be scalar or table -valued
Ø Static class functions
Ø Deterministic functions
l Using a function in a query
SELECT s.name FROM Supplier s
WHERE dbo.distance ( s.x, s.y, @x, @y ) < 3
dbo.distance(
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 10

11. Creating A Procedure
CREATE PROCEDURE check_inventory
EXTERNAL NAME ‘events:CInventory.check_level’
‘events:CInventory.check_level’
DROP PROCEDURE check_inventory
l Procedures not called from queries
Ø Can contain SQL queries, updates or DDL
Ø Can return results directly to client
Creating A Trigger
CREATE TRIGGER supplier_event ON supplier
AFTER INSERT, UPDATE
EXTERNAL NAME ‘events:CNotif.Supp_Event’
‘events:CNotif.Supp_Event’
DROP TRIGGER supplier_event
l Similar to procedures, plus
l Access to inserted, deleted tables
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 11

12. Creating A Type
l Create or drop a type
CREATE TYPE Point
EXTERNAL NAME ‘geom:Point’
‘geom:Point’
DROP TYPE Point
l Using a type
CREATE TABLE Supplier (
id INTEGER PRIMARY KEY,
name VARCHAR(20),
location Point )
l Using a type method in a query
SELECT s.name FROM Supplier s
WHERE s.location::distance( @point ) < 3
Query Optimization
l Automatically gather function statistics
Ø Value histograms, execution cost
l Reorder of predicate evaluation
Ø Based on execution cost and statistics
l Function indexes
Ø Speed up expensive functions
Ø Extends computed column indexes
and index views
l Implied and residual predicates
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 12

13. Summary
l Richer server programming model
Ø Any .NET framework language
Ø Same mid - and server -tier data access:
mid- server-
ADO. NET
Ø Same IDE, project model, debugging, tools
l SQL Server hosting of .NET runtime
Ø Safety, security, scalability, speed
l SQL Server .NET features
Ø Functions, stored procedures, triggers,
types, aggregates
Demos
l Sample code for function, stored procedure, and type
l Assemblies
Ø Safe versus external access
l Functions and stored procedures
Ø Creation and execution
Ø Data access in-process via ADO .NET
in-
l Types
Ø Type contract
Ø Create type
Ø Create table with column of user-defined type
user-
Ø Create index on column of user-defined type
user-
Ø Insert and query the table
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 13

14. © 2001 Microsoft Corporation. All rights reserved.
PDC 2001
October 22-26, 2001
© 2001 Microsoft Corporation. All rights reserved. 14