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Presented by, MySQL & O’Reilly Media, Inc. MySQL, LINQ and the ADO.NET Entity Framework Reggie Burnett, MySQL David Sceppa, Microsoft

MySQL, LINQ and the ADO_NET Entity Framework Presentation

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Page 1: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Presented by,MySQL & O’Reilly Media, Inc.

MySQL, LINQ and theADO.NET Entity Framework

Reggie Burnett, MySQLDavid Sceppa, Microsoft

Page 2: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Agenda From DataSets to data access layers Introducing LINQ Using LINQ to access your data The ADO.NET Entity Framework Introducing ADO.NET Data Services Summary

Page 3: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Working with DataSets Basic example

//Execute a query, retrieve and store the resultsconnectionString = "Data Source=localhost;User ID=...;";commandText = "SELECT CompanyName, City FROM Customers " + "WHERE Country = ?Country";adapter = new MySqlDataAdapter(commandText, connectionString);adapter.SelectCommand.Parameters.AddWithValue("?Country", "Brazil");table = new DataTable();adapter.Fill(table);

//Display the resultsDataGridView resultsGrid = new DataGridView();resultsGrid.DataSource = table;

//Submit pending changescommandBuilder = new MySqlCommandBuilder(adapter);adapter.Update(table);

Page 4: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Working with DataSets Benefit

• Rapid development - Designers, wizards, bound controls make it easy to write code and generate user interface

Drawbacks• Developers must become SQL experts to

build advanced queries• Code becomes more complex when app

model and database schema diverge

Page 5: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Moving to data access layers Focus on your application model

• Queries expressed in terms of app model• Classes track their own changes

Data access layer responsible for• Translating into SQL queries• Returning results as objects• Submitting pending changes

Page 6: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Moving to data access layers Basic example

//Partial class to separate data access codepublic class Customer {

//Add methods to return data public static List<Customer> GetCustomers(string country) { List<Customer> results = new List<Customer> (); MySqlConnection connection = new MySqlConnection(connectString); connection.Open(); MySqlCommand command = new MySqlCommand(queryString, connection); command.Parameters.AddWithValue("?Country", country); MySqlDataReader reader = command.ExecuteReader(); while (reader.Read()) results.Add(Customer.CreateFromReader(reader)); return results; }

//Support tracking and submitting changes private string origCustomerId, origCompanyName, ...; public void SubmitChanges() { ... }}

Page 7: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Moving to data access layers Benefit

• Division of labor - Manage data access code separately, only subset of developers need to become SQL gurus

Drawbacks• Data access code quickly gets complex

Classes that span multiple tables Handling inheritance hierarchies Note: Patterns and frameworks emerge

Page 8: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Introducing LINQ What is LINQ?

• Stands for Language INtegrated Query• Allows developers to query data structures

using SQL-like syntax from within their application’s code

• Is available to both C# and Visual Basic developers in Visual Studio 2008

Page 9: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Introducing LINQ LINQ Example - Querying an array

//Create an array of integersint[] myarray = new int[] { 49, 28, 20, 15, 25, 23, 24, 10, 7, 34 };

//Create a query for odd numbersvar oddNumbers = from i in myarray where i % 2 == 1 select i;

//Display the results of the queryforeach (int i in oddNumbers) Console.WriteLine(i);

//Create a query for odd numbers, sortedvar oddNumbers = from i in myarray where i % 2 == 1 orderby i select i;

//Create a query for odd numbers, sorted in descending ordervar oddNumbers = from i in myarray where i % 2 == 1 orderby i descending select i;

//Create a query for odd numbersvar oddNumbers = from i in myarray where i % 2 == 1 select i;

//Compose the original query to create a query for odd numbersvar sorted = from i in oddNumbers orderby i descending select i;

Page 10: MySQL, LINQ and the ADO_NET Entity Framework Presentation

LINQ-enabled classes Collection classes extended

• Arrays, Hashtable, List<T>, etc. LINQ to DataSet• Extended for untyped and strongly typed LINQ to XML Data access technologies• LINQ to SQL• LINQ to Entities

Page 11: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Agenda From DataSets to data access layers Introducing LINQ Using LINQ to access your data The ADO.NET Entity Framework Introducing ADO.NET Data Services Summary

Page 12: MySQL, LINQ and the ADO_NET Entity Framework Presentation

LINQ to DataSet DataSet class enhanced to support LINQ

• Available via typed and untyped DataSet

Dim ordersQuery = From o In dataSet.Orders _ Where o.CustomerID = "ALFKI" _ Select o

For Each o As NorthwindDataSet.OrdersRow In ordersQuery Console.WriteLine("{0} {1,10:d}", _ o.OrderID, o.OrderDate) Next o

Page 13: MySQL, LINQ and the ADO_NET Entity Framework Presentation

LINQ to DataSet Benefits

• Quickest way to use LINQ w/ .NET 2.0 feature set

• Supports query capabilities previously unavailable using a DataSet

• Returns results as series of DataRows or as anonymous types

Limitations• All client-side processing

Page 14: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Benefits• Rapid application development scenarios• Query processing performed at the server• Designer makes mapping classes to tables

simple Limitations

• Supports limited mapping scenarios• No provider model for extensibilityNo provider model for extensibility

LINQ to SQL Benefits

• Rapid application development scenarios• Query processing performed at the server• Designer makes mapping classes to tables

simple Limitations

• Supports limited mapping scenarios

Page 15: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Agenda From DataSets to data access layers Introducing LINQ Using LINQ to access your data The ADO.NET Entity Framework Introducing ADO.NET Data Services Summary

Page 16: MySQL, LINQ and the ADO_NET Entity Framework Presentation

What is LINQ to Entities?• LINQ implementation of the Entity Data Model

What is the Entity Data Model?• Definition for your application model• Map between app model, database schema• Advanced mapping scenarios supported One entity mapped across multiple tables Multiple inheritance hierarchy mappings Many-to-many without "link" table in model

What is LINQ to Entities?• LINQ implementation of the Entity Data Model

LINQ to Entities

Page 17: MySQL, LINQ and the ADO_NET Entity Framework Presentation

LINQ to DataSet DataSet class enhanced to support LINQ

• Available via typed and untyped DataSet

Dim ordersQuery = From o In dataSet.Orders _ Where o.CustomerID = "ALFKI" _ Select o

For Each o As NorthwindDataSet.OrdersRow In ordersQuery Console.WriteLine("{0} {1,10:d}", _ o.OrderID, o.OrderDate) Next o

Page 18: MySQL, LINQ and the ADO_NET Entity Framework Presentation

LINQ to Entities or LINQ to SQL? LINQ to SQL

• Shipped with Visual Studio 2008 and .NET 3.5• Emphasis on rapid application development• Supports Microsoft SQL Server family of databases

LINQ to Entities• Will ship as an update to .NET 3.5• Offers a provider model for third-party databases• Designed for enterprise-grade data scenarios• Higher level of abstraction for programming databases• Just one layer of the overall ADO.NET Entity Framework

Page 19: MySQL, LINQ and the ADO_NET Entity Framework Presentation

LINQ to Entities: Generating Queries Converting LINQ queries to SQL

• Compiler converts code into a LINQ expression tree• LINQ to Entities converts LINQ expression tree into

a DbCommandTree based on mapping information DbCommandTree expressed in terms of the

database schema• ADO.NET provider generates a DbCommand• LINQ to Entities executes the DbCommand,

assembles results into the structure(s) specified in the LINQ query

Page 20: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Agenda From DataSets to data access layers Introducing LINQ Using LINQ to access your data The ADO.NET Entity Framework Introducing ADO.NET Data Services Summary

Page 21: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Entity Framework: LINQ and more ADO.NET Entity Framework Layers

• First implementation of Entity Data Model (EDM)

• Includes a text-based queryquery language (Entity SQL)

• New Provider – EntityClient• New ORM stack (Object Services)

leverages Entity Client• LINQ support over Entities• An evolution of ADO.NET

preserving customer investment

ADO.NET Provider

EntityClient

ObjectServices

LINQ to Entities

Page 22: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Entity Framework Query Options LINQ to Entities

Sweet spot:• Strongly typed queries and results Compile-time type checking and Intellisense

• Results returned as objects: entities / projections• Queries must be well defined at compile time

var ordersQuery = from o in context.Orders where o.Customers.CustomerID == "ALFKI" select o;

foreach (var o in ordersQuery) Console.WriteLine("{0} {1:d}", o.OrderID, o.OrderDate);

Page 23: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Entity Framework Query Options ObjectQuery<T> / ObjectQuery(Of T)

Sweet spot:• Strongly typed results, text-based queries• Results returned as objects: entities / projections• Queries more loosely defined at compile-time

Dim eql As String = "SELECT VALUE o FROM Orders AS o " & _ " WHERE o.Customer.CustomerID = 'ALFKI'"Dim ordersQuery = context.CreateQuery(Of Order)(esql)

For Each o As Order In ordersQuery Console.WriteLine("{0} {1,10:d} ", o.OrderID, o.OrderDate)Next o

Page 24: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Entity Framework Query Options EntityClient Provider

Sweet spot:• Untyped queries and results• Results returned as DataReaders• Queries can be generated purely at run time No application model classes needed at compile time

string eSql = "SELECT VALUE o FROM NorthwindEntities.Orders AS o " + "WHERE o.Customers.CustomerID = 'ALFKI'";EntityCommand cmd = new EntityCommand(eSql, connectionString);EntityDataReader rdr = cmd.ExecuteReader();while (rdr.Read()) Console.WriteLine("{0} {1:d}", rdr["OrderID"], rdr["OrderDate"]);

Page 25: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Agenda From DataSets to data access layers Introducing LINQ Using LINQ to access your data The ADO.NET Entity Framework Introducing ADO.NET Data Services Summary

Page 26: MySQL, LINQ and the ADO_NET Entity Framework Presentation

ADO.NET Data Services Formerly known as "Project Astoria"• Part of ASP.NET Extensions Preview• Integrated into .NET Framework going forward Targeting Web development technologies• Silverlight and AJAX• Data returned via Web-friendly formats ATOM (XML-based) and JSON

Page 27: MySQL, LINQ and the ADO_NET Entity Framework Presentation

ADO.NET Data Services Service exposed via lightweight data access API• Supply both location and query as a URI: http://myserver/data.svc/Customers[ALFKI]/Orders

• Query converted to LINQ inside of service• Supports submitting changes Specialized Entity Framework logic for submitting changes

Online data hosting service available For more information:• http://astoria.mslivelabs.com

Page 28: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Agenda From DataSets to data access layers Introducing LINQ Using LINQ to access your data The ADO.NET Entity Framework Introducing ADO.NET Data Services Summary

Page 29: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Summary - LINQ Represents a revolution for developers• Query your objects using SQL-like syntax• LINQ to DataSet Rich query scenarios for data residing in a DataSet

• LINQ to Entities Provider model for working with other data stores Supports enterprise mapping scenarios

Page 30: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Summary - ADO.NET Entity Framework More than just LINQ to Entities• Also supports text-based query language – ESQL• ObjectQuery<T> for strongly typed results• EntityClient for reader-based results Enterprise-grade data scenarios Provider model for working with other data stores

Page 31: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Summary - ADO.NET Data Services Designed for Silverlight, AJAX environments Lightweight API, connect and query via URI Retrieve results via familiar formats• ATOM• JSON

Page 32: MySQL, LINQ and the ADO_NET Entity Framework Presentation

Questions?