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LINQ 2 SQL By, Shahzad Sarwar. What you should know, before starting Anonymous function Anonymous type Anonymous Methods Lamda expression Collection Initializers.

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Presentation on theme: "LINQ 2 SQL By, Shahzad Sarwar. What you should know, before starting Anonymous function Anonymous type Anonymous Methods Lamda expression Collection Initializers."— Presentation transcript:

1 LINQ 2 SQL By, Shahzad Sarwar

2 What 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)

3 What is the problem? Class!=Data 1. strongly-typed queries, what ? 2. strongly-typed results Benefits 1. IntelliSense 2. Compile-time error checking.

4 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:

5 Current 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

6 Current 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

7 A view of LINQ LINQ 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 + ) LINQ to SQL- DLinq Direct sql server ( )

8 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 {} LINQ to XML = xlinq The low-level XmlReader/XmlWriter API in.NET today. {System.Xml.Linq} PLINQ Query 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.

9 Conceptual View (LINQ)

10 Conceptual View (LINQ to Dataset)

11 Conceptual View (LINQ 2 entities)

12 Conceptual View ( PLINQ)

13 References [LINQ to Dataset] introduction-to-linq-to-dataset.aspx [LINQ to entities] entities-smackdown.aspx

14 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. Sample Application on the fly Sample Application: Sample Add, delete, edit Example What next ??????????????????????????? It is over…

15 DataContext 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?

16 Context Management Four Approaches 1. 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/atomic Not 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

17 Context 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

18 Architecture Guide Lines References: hive/2007/05/10/9322.aspx tier-scenarios-saving-an-object/ datacontext.aspx linq-s-datacontext-to-re-create-your-database-for-testing.aspx framework-design-guidelines.aspx framework-design-guidelines.aspx

19 Code Generation 2 Options VS Studio OR Designer SQLMetal Code Understanding Explore XML Mapping file Generated classes dataConext,Database, Table, relationships Example

20 Query 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: expression-tree-visualizer.aspx

21 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

22 LINQDataSource Like sqlDataSource Example 1 (Wizard View, declarative View ) Overriding events Selecting event Example 2

23 Using 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.

24 LINQ2SQL Customization By Store Procedure Example Object validation (Partial classes) Example Customize entity class ( 1 to m mapping ) Example

25 Inheritance In OR Mapping, 3 Type Example

26 Table per Class Hierarchy [Example]

27 Table per Subclass

28 Table per Concrete Class

29 LINQ Dev. Tools Visual LINQ Query Builder through a friendly interface [Demo] LINQPad Development tool [Demo]

30 Performance Benchmark 1 References performance-part-1.aspx

31 Performance 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: vs.html

32 Performance But consider Productivity SQL being first class language in VS Caching of DB. Change tracking optimization So Over a Great Milestone in Development process

33 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 …………………


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