LINQ 2 SQLLINQ 2 SQL By, Shahzad Sarwar

What you should know, before startingWhat you should know, before starting

• Anonymous function• Anonymous type• Anonymous Methods• Lamda expression• Collection Initializers• Object Initializers• Extension methods• Type Inference• Automatic properties• Partial Methods• Generic• Projection (Later)• Expression Tree (Later)

• What is the problem?

Class!=Data• 1. strongly-typed queries , what ?• 2. strongly-typed results• Benefits

1. IntelliSense

2. Compile-time error checking.

• What is Linq to SQL?1.OR Mapper API

2.Syntax to query ( LINQ to objects )

3.Tools

• What r OR Mappers(OR/M)? • Not ORM?• What is Object Role Modeling (ORM)?

• Associated language FORML (Formal Object-Role Modeling Language)

• Supported by Visio and Microsoft Architect

• References: http://www.orm.net/

Current Solutions in marketCurrent Solutions in market• .NET Persistence • BBADataObjects • DataObjects.NET • Data Tier Modeler for .NET • DotNorm • Eldorado.NET • Enterprise Core Objects (ECO™) • Entity Broker • eXpress Persistent Objects for .NET • FastObjects.NET • JC Persistent Framework • LLBLGen Pro • ModelWorks • Nhibernate • Nolics.NET

Current Solutions in marketCurrent Solutions in market• Norm • Norpheme • ObjectBroker • ObjectSpaces • ObjectSpark • Objectz.NET • OJB.NET • OPF.Net (Object Persistent Framework) • ORM.NET • Pragmatier Data Tier Builder • RapTier • Sisyphus Persistence Framework • TierDeveloper • Bob.NET • ObjectPersistor.NET • Genome

A view of LINQA view of LINQLINQ Consist of :• Total 6 LINQ implementations • 3 general LINQ technologies • 2 related to relational databases (OR/M)• 1 Future Technologies

• LINQ to Objects Over objects , system.linq

• LINQ to Dataset over dataset ( LINQ to objects + system.data.dataextension )

• LINQ to SQL- DLinq Direct sql server ( system.data.linq )

• LINQ to entities • entities framework ( a part of the ADO.NET Entity Framework which

allows LINQ query capabilities) • The Entity Data Model (EDM) is a conceptual data

{System.data.entity}

• LINQ to XML = xlinq • The low-level XmlReader/XmlWriter API in .NET today.

{System.Xml.Linq}

• PLINQQuery execution engine accepts any LINQ-to-Objects or LINQ-to-XML query and automatically utilizes multiple processors or cores for execution when they are available.

Conceptual View Conceptual View (LINQ)(LINQ)

Conceptual View Conceptual View (LINQ to Dataset)(LINQ to Dataset)

Conceptual View Conceptual View (LINQ 2 entities)(LINQ 2 entities)

Conceptual View Conceptual View ( PLINQ)( PLINQ)

ReferencesReferences

[LINQ to Dataset]• http://blogs.msdn.com/adonet/archive/2007/01/26/querying-datasets-

introduction-to-linq-to-dataset.aspx• http://msdn.microsoft.com/en-us/vbasic/bb688086.aspx• http://msdn.microsoft.com/en-us/library/bb386977.aspx• http://www.danielmoth.com/Blog/2007/07/linq-to-dataset.html• http://channel9.msdn.com/posts/DanielMoth/LINQ-to-DataSet/

[LINQ to entities]• http://msdn.microsoft.com/en-us/library/bb386964.aspx• http://dotnetaddict.dotnetdevelopersjournal.com/adoef_vs_linqsql.htm• http://blogs.msdn.com/kaevans/archive/2008/01/29/linq-to-sql-vs-linq-to-

entities-smackdown.aspx• http://msdn.microsoft.com/en-us/library/cc161164.aspx

What is difference LINQ to SQ L and LINQ to Entities?

• 1:1 vs many to many , complex mapping • sql only , any database .... so run in database specfic pattern.

http://msdn.microsoft.com/en-us/library/cc161164.aspx

• Sample Application on the fly• Sample Application:

Sample Add , delete , edit

Example

What next ??????????????????????????? It is over…

DataContextDataContext• Connection like class (Mixture of a lot of objects)• Caching n change tracking• Example

• Log• ExecuteCommand• GetTable• ExecuteQuery• Refresh• ObjectTrackingEnabled• Transaction

• Cases:• Nested Query• Cache Query / Multiple context• ToList()

• What is Projection?

Context ManagementContext Management

• Four Approaches1. Create a new Context for each atomic operation (Application level

management) Problem: pass data objects or the data context itself around to other components in your

application.E.g.: if you use business objects there's no real clean way to get a context passed between business objects.

2.Create a global DataContext and handle all operations against this single DataContext object

Problem:In other words if you have multiple simulataneous data operations that might not be

directly linked/atomicNot possible to do simple update.....?and Options such ObjectTrackingEnabled or DeferredLoadingEnabled can't be set

easily Works for desktop , not for Web because of threading ........

Context ManagementContext Management

3.Create a thread specific DataContext

Request specific DataContext that is tied to the active thread,Web request to the active ASP.NET HttpContext.

Example

Factory Pattern

4. Create a per business object DataContext

Architecture Guide LinesArchitecture Guide Lines

References:• http://mtaulty.com/CommunityServer/blogs/mike_taultys_blog/

archive/2007/05/10/9322.aspx• http://jonkruger.com/blog/2008/02/10/linq-to-sql-in-

disconnectedn-tier-scenarios-saving-an-object/• http://andrewtokeley.net/archive/2008/07/06/mocking-linq-to-sql-

datacontext.aspx• http://devlicio.us/blogs/derik_whittaker/archive/2008/05/21/using-

linq-s-datacontext-to-re-create-your-database-for-testing.aspx• http://www.west-wind.com/weblog/posts/246222.aspx• http://blogs.msdn.com/mirceat/archive/2008/03/13/linq-

framework-design-guidelines.aspx• http://msdn.microsoft.com/en-us/library/bb882661.aspx

Code GenerationCode Generation

• 2 Options • VS Studio OR Designer• SQLMetal

• Code Understanding • Explore

• XML Mapping file• Generated classes

dataConext ,Database, Table, relationshipsExample

Query pipelineQuery pipeline• LINQ 2 Objects = IEnumerable • LINQ 2 SQL= IQueryable

public interface IQueryable : IEnumerable { Type ElementType { get; } Expression Expression { get; } IQueryProvider Provider { get; } }

• What is Expression Tree?a method of translating executable code into data.

• Add-ons:• Query Visualizer• Expression Tree Visualizer• Example

• Out of processor , Grammar , sql processor• Various Stages ( Out of scope )• 1-Many mapping b/q LINQ grammer to db sql References:• http://blogs.msdn.com/charlie/archive/2008/01/31/expression-tree-basics.aspx• http://blogs.msdn.com/charlie/archive/2008/02/13/linq-farm-seed-using-the-

expression-tree-visualizer.aspx

Joins n Lazy Loading Joins n Lazy Loading

• Types of Joins• Inner Join

• Left Outer Join

• Right Outer Join

• Cross Join

• Example• LINQ implementation of Joins• Deferred Loading of objects• DataLoadOptions/DeferredLoadingEnabled property• AssociateWith Property

LINQDataSourceLINQDataSource

• Like sqlDataSource• Example 1 (Wizard View , declarative View )

• Overriding events• Selecting event• Example 2

Using Store ProcedureUsing Store Procedure

• Add Store procedures to Model• Example • Add function to Models• Example• Difference b/w Store Procedure n function

• for computations , for Business logic

• Functions can be called inside select/update/delete stmt but not the procedures.

LINQ2SQL CustomizationLINQ2SQL Customization

• By Store Procedure• Example• Object validation (Partial classes)• Example• Customize entity class ( 1 to m mapping )• Example

InheritanceInheritance• In OR Mapping, 3 Type• Example

Table per Class HierarchyTable per Class Hierarchy

[Example]

Table per SubclassTable per Subclass

Table per Concrete ClassTable per Concrete Class

LINQ Dev. ToolsLINQ Dev. Tools

• Visual LINQ Query Builder through a friendly interface

http://code.msdn.microsoft.com/vlinq

[Demo]

• LINQPad http://www.linqpad.net/

Development tool

[Demo]

PerformancePerformance• Benchmark 1

References• http://blogs.msdn.com/ricom/archive/2007/06/22/dlinq-linq-to-sql-

performance-part-1.aspx• http://blogs.msdn.com/ricom/archive/2007/06/22/dlinq-linq-to-sql-

performance-part-1.aspx

PerformancePerformance

• Adventure Db , Store procedure

• So, comparing to the raw ADO.NET - DAAB is 8% slower and LINQ is 28% slower.Comparing to DAAB - LINQ is 18% slower.

Reference:• http://alexpinsker.blogspot.com/2007/07/benchmarking-linq-

vs.html

PerformancePerformance

• But consider• Productivity• SQL being first class language in VS• Caching of DB.• Change tracking optimization

So Over a Great Milestone in Development process

What is Left………………..What is Left………………..

• Design Pattern for LINQ to SQL• XLINQ• LINQ to Dataset• LINQ to entities• PLINQ• n…………………….• …..• …………..• ………………..• So Wait for Next presentation on LINQ …………………