By: Luis Carranco CIS764 - Fall 2008

 What is LINQ  Architecture  How does it work?  Samples/Demo  Why to use LINQ? 2

 Language Integrated Query for.NET  C# 3.0, VB 9.0  Unifies the way data can be retrieved from any object that implements the IEnumerable interface. ◦ Relational data ◦ XML ◦ Object collections 3

44 Image taken from LINQ for Visual C# Fabio Ferracchiati

5 LINQ to SQL SQL Server from c in db.Customers where c.City == "London" select c.CompanyName from c in db.Customers where c.City == "London" select c.CompanyName Execute (Iteration) SELECT CompanyName FROM Customer WHERE City = 'London' SELECT CompanyName FROM Customer WHERE City = 'London' SQL Query Rows Objects db.Customers.Add(c1); c2.City = “Seattle"; db.Customers.Remove(c3); db.Customers.Add(c1); c2.City = “Seattle"; db.Customers.Remove(c3); SubmitChanges() INSERT INTO Customer … UPDATE Customer … DELETE FROM Customer … INSERT INTO Customer … UPDATE Customer … DELETE FROM Customer … DML

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 Only one syntax to retrieve data from any data source  Productivity. Focus on business  Compiler checks queries and type safety  Avoid SQL, XPath  Rich set of instructions to implement complex queries that support data aggregation, joins, sorting, and much more 7

 The LINQ Project Accessed 11/16/  LINQ for Visual C# Fabio Claudio Ferracchiati. 1st Edition. Apress.  Programming Microsoft LINQ. Paolo Pialors, Marco Russo. MSPress. 8

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