We use many different types of query

We use many different types of query

• We use many different types of query

• SQL, XQuery/XPath, DataView row filters, etc.

• Maybe we could enhance productivity by...

• Deciding on one query expression syntax
• Enabling compilers to check queries & results
• Allow extensibility to target all kinds of data

C#3 and VB9 Language Enhancements

• C#3 and VB9 Language Enhancements

• Building to LINQ to Objects

• LINQ to XML

• LINQ to SQL

• LINQ to DataSets

Ship with Visual Studio 2008

• Ship with Visual Studio 2008

• Contain language features that enable LINQ

• Necessary for LINQ, but not sufficient...

• Also need .NET FX 3.5

• Contains a lot of new classes that make LINQ work – we’ll see some later

Creating XML

• Creating XML

• Constructors lend themselves to nesting
• Can use LINQ (over anything) to build XML

• Querying

• Use normal axes from XML infoset
• Get full power of query expressions over XML
• Select, where, group by, etc.

• Xml Namespaces

DataContext is the central class

• DataContext is the central class

• Use code-gen for ORM

• SQL is only submitted when needed

• Parent-child relationships are respected

• Control of deferred loading

• Can insert/update/delete

• Transactionally, with concurrency checks

Query expressions over in-memory data

• Query expressions over in-memory data

• Works with untyped or typed DataSets

• If query returns some kind of DataRow: -

• Can yield results as a DataView
• ...and therefore databind to those results

A combination of new language features, and new fx3.5 classes (with extension methods)

• A combination of new language features, and new fx3.5 classes (with extension methods)

• A common query expression syntax

• Freedom to implement across different kinds of data

• It’s TYPED...

• The compiler can check your queries
• The compiler can check your results

Today’s sample code via

• Today’s sample code via

• http://www.martinparry.com

• MSDN Nuggets by Mike Taulty

• http://www.microsoft.com/uk/msdn/nuggets

Visit http://msdn.co.uk

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