B_110500002

  • 817 views
Uploaded on

 

More in: Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
817
On Slideshare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
49
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. MySQL, LINQ and the ADO.NET Entity Framework
    • Reggie Burnett, MySQL
    • David Sceppa, Microsoft
  • 2. 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
  • 3. Working with DataSets
    • Basic example
    //Execute a query, retrieve and store the results connectionString = "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 results DataGridView resultsGrid = new DataGridView (); resultsGrid.DataSource = table; //Submit pending changes commandBuilder = new MySqlCommandBuilder (adapter); adapter.Update(table);
  • 4. 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
  • 5. 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
  • 6. Moving to data access layers
    • Basic example
    //Partial class to separate data access code public 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( &quot;?Country&quot; , 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() { ... } }
  • 7. 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
  • 8. 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
  • 9. Introducing LINQ
    • LINQ Example - Querying an array
    //Create an array of integers int [] myarray = new int [] { 49, 28, 20, 15, 25, 23, 24, 10, 7, 34 }; //Create a query for odd numbers var oddNumbers = from i in myarray where i % 2 == 1 select i; //Display the results of the query foreach ( int i in oddNumbers) Console .WriteLine(i); //Create a query for odd numbers, sorted var oddNumbers = from i in myarray where i % 2 == 1 orderby i select i; //Create a query for odd numbers, sorted in descending order var oddNumbers = from i in myarray where i % 2 == 1 orderby i descending select i; //Create a query for odd numbers var oddNumbers = from i in myarray where i % 2 == 1 select i; //Compose the original query to create a query for odd numbers var sorted = from i in oddNumbers orderby i descending select i;
  • 10. 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
  • 11. 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
  • 12. 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 = &quot;ALFKI&quot; _ Select o For Each o As NorthwindDataSet.OrdersRow In ordersQuery Console.WriteLine( &quot;{0} {1,10:d}&quot; , _ o.OrderID, o.OrderDate) Next o
  • 13. 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
  • 14. 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
    • 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 extensibility
  • 15. 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
  • 16.
    • What is LINQ to Entities?
      • LINQ implementation of the Entity Data Model
    LINQ to Entities
    • 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 &quot;link&quot; table in model
  • 17. 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 = &quot;ALFKI&quot; _ Select o For Each o As NorthwindDataSet.OrdersRow In ordersQuery Console.WriteLine( &quot;{0} {1,10:d}&quot; , _ o.OrderID, o.OrderDate) Next o
  • 18. 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
  • 19. 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
  • 20. 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
  • 21. Entity Framework: LINQ and more
    • ADO.NET Entity Framework Layers
      • First implementation of Entity Data Model (EDM)
      • Includes a text-based query query 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
  • 22. 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 == &quot;ALFKI&quot; select o; foreach ( var o in ordersQuery) Console .WriteLine( &quot;{0} {1:d}&quot; , o.OrderID, o.OrderDate);
  • 23. 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 = &quot;SELECT VALUE o FROM Orders AS o &quot; & _ &quot; WHERE o.Customer.CustomerID = 'ALFKI'&quot; Dim ordersQuery = context.CreateQuery( Of Order)(esql) For Each o As Order In ordersQuery Console.WriteLine( &quot;{0} {1,10:d} &quot; , o.OrderID, o.OrderDate) Next o
  • 24. 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 = &quot;SELECT VALUE o FROM NorthwindEntities.Orders AS o &quot; + &quot;WHERE o.Customers.CustomerID = 'ALFKI'&quot; ; EntityCommand cmd = new EntityCommand (eSql, connectionString); EntityDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) Console .WriteLine( &quot;{0} {1:d}&quot; , rdr[ &quot;OrderID&quot; ], rdr[ &quot;OrderDate&quot; ]);
  • 25. 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
  • 26. ADO.NET Data Services
    • Formerly known as &quot;Project Astoria&quot;
    • 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
  • 27. 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
  • 28. 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
  • 29. 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
  • 30. 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
  • 31. Summary - ADO.NET Data Services
    • Designed for Silverlight, AJAX environments
    • Lightweight API, connect and query via URI
    • Retrieve results via familiar formats
    • ATOM
    • JSON
  • 32. Questions?