Difference between revisions of "DD Class9"

esse quam videri
Jump to: navigation, search
m (Text replacement - "syntaxhighlight lang="csharp" line="1" " to "syntaxhighlight lang="csharp"")
 
(12 intermediate revisions by the same user not shown)
Line 1: Line 1:
 
[[Category:Data Design]]
 
[[Category:Data Design]]
  
−
==DataReader==
+
==Repo Pattern==
  
−
*DataReader http://iam.colum.edu/dd/classsource/ado/dataReader.aspx [http://iam.colum.edu/dd/gbrowser.php?file=/classsource/ado/dataReader.aspx source]  
+
Definition from P of EE http://martinfowler.com/eaaCatalog/repository.html
 +
MSDN [http://msdn.microsoft.com/en-us/library/ff649690.aspx The Repository Pattern]
  
 +
The repository pattern is a nice way to abstract data fetching logic and easily separate concerns from different layers of your app. It allows of to quickly refactor and swap repos.
  
 +
First we can start with the cheese definition
  
−
1 Connection Object
+
<syntaxhighlight lang="csharp">
−
<csharp>
+
public class Cheese
−
//Connection string comes from web config
+
    {
−
SqlConnection objConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["cheeseConnectionString"].ConnectionString);            
+
       
−
</csharp>
+
        public int CheeseID { get; set; }
 +
       
 +
        public string CheeseName { get; set; }
 +
       
 +
        public string CheeseDescription { get; set; }
 +
    }
 +
</syntaxhighlight>
 +
Then interface for the repo
 +
<syntaxhighlight lang="csharp">
 +
public interface IRepository<T>
 +
    {
 +
        T GetById(int id);
 +
        List<T> GetItems();
 +
        void Add(T entity);
 +
        void Remove(T entity);
 +
    }
 +
</syntaxhighlight>
 +
Now we want to expand the interface definition to cheeses
 +
<syntaxhighlight lang="csharp">
 +
/// <summary>
 +
    /// ICheeseRepo Changes the type of the Generic Repo To Cheese
 +
    /// </summary>
 +
    public interface ICheeseRepo : IRepository<Cheese>
 +
    {
 +
        List<Cheese> GetItems();
 +
        List<Cheese> GetCheeses(); //New Method To Get Cheeses
 +
        //May want to expand the definition to get cheese by name
 +
        //Cheese GetByName(string name)
 +
    }
 +
</syntaxhighlight>
 +
Finally the repo interface can then be implemented like this
 +
<syntaxhighlight lang="csharp">
 +
public class TestCheeseRepository : ICheeseRepo
 +
    {
  
−
web.config connection strings
+
        //could grab these from the Application Object
 +
        private static List<Cheese> fakeCheeses =
 +
            new List<Cheese> { new Cheese { CheeseID=1, CheeseName="test1", CheeseDescription = "test desc 1" },
 +
                new Cheese { CheeseID=2, CheeseName="test2", CheeseDescription = "test desc 2" },
 +
                new Cheese { CheeseID=2, CheeseName="test3", CheeseDescription = "test desc 3" }
 +
            };
  
−
<xml>
 
−
<configuration>
 
−
 
−
              <connectionStrings>
 
−
 
−
  <add name="cheeseConnectionString" connectionString="Data Source=iamdb;Initial Catalog=cheese;User ID=student;Password=Student" providerName="System.Data.SqlClient"/>
 
−
      </connectionStrings>
 
−
</xml>
 
  
−
2 Command Object
+
        #region ICheeseRepo Members
−
<csharp>string strSQL = "SELECT CheeseName,CheeseDescription FROM cheese";
+
        public List<Cheese> GetItems()
−
   
+
        {
−
    string strResultsHolder = "";
+
            return GetCheeses();
−
   
+
        }
−
    SqlCommand objCommand = new SqlCommand(strSQL, objConnection);
 
−
</csharp>
 
  
−
3 Reader and Reading
 
−
<csharp>
 
−
SqlDataReader objDataReader = null;                            //Reader to read through the result
 
−
    try
 
−
    {
 
−
        objConnection.Open();                                      //Open Connection
 
−
        objDataReader = objCommand.ExecuteReader();
 
  
−
         while (objDataReader.Read() == true)
+
         public List<Cheese> GetCheeses()
 
         {
 
         {
−
             strResultsHolder += String.Format("<b>{0}</b>:{1}<br /><br />",
+
             return fakeCheeses.ToList();
−
                objDataReader["CheeseName"], objDataReader["CheeseDescription"]);
 
 
         }
 
         }
−
    }
 
−
    catch (Exception e)
 
−
    {
 
−
        lblErr.Text = "Connection failed to open successfully.<br/>";
 
−
        lblErr.Text += e.ToString();
 
−
    }
 
−
    finally
 
−
    {
 
−
        objDataReader.Close();      //Close Reader
 
−
        objConnection.Close();      //Close Connection
 
  
−
    }
+
        #endregion
−
    //Write results
 
−
    divListCheese.InnerHtml = strResultsHolder;
 
−
}
 
  
−
</csharp>
+
        #region IRepository<Cheese> Members
  
 +
        public Cheese GetById(int id)
 +
        {
 +
            //linq statement to find cheese by ID
 +
            var currentCheese = from c in fakeCheeses where c.CheeseID == id select c;
 +
            return currentCheese.FirstOrDefault();
 +
        }
  
−
==Review First Normal Form==
+
        public void Add(Cheese entity)
 +
        {
 +
            fakeCheeses.Add(entity);
 +
        }
  
−
Let build the example for the homework.
+
        public void Remove(Cheese entity)
 +
        {
 +
            fakeCheeses.Remove(entity);
 +
        }
  
−
==Build Interface to GameDB==
+
        #endregion
  
−
'''Games'''
+
        //added statement to find cheese by name
−
{| class="wikitable" cellpadding="5" cellspacing="0"
+
        public Cheese GetByName(string name)
−
!GameTitle !!  GameGenre !! DeveloperName !! Platform(s) !! Year !! DeveloperWebsite !! GameWebsite
+
        {
−
|-
+
            //linq statement to find cheese by name
−
| Quake1 || FPS || id || Dos || 1996 || http://www.idsoftware.com/ || http://www.idsoftware.com/games/quake/quake/
+
            var currentCheese = from c in fakeCheeses where c.CheeseName == name select c;
−
|-
+
            return currentCheese.FirstOrDefault();
−
| Diablo|| RPG|| Blizzard || Windows 95|| 1996 || http://www.blizzard.com/  || http://www.blizzard.com/diablo/
+
        }
−
|-
+
    }
−
| SimCity || Sim || Interplay || Dos || 1993 || http://www.interplay.com/  || http://www.maxis.com/
+
</syntaxhighlight>
−
|}
 
  
−
Tables Games, Developers, Websites, Platforms?
+
Link to the implememtation http://iam.colum.edu/datadesign/gbrowser.php?file=/App_code/Repo/CheeseRepo.cs
  
−
Build Views
+
Now to use the Repo
  
−
==Nesting Data Bound Controls==
+
http://iam.colum.edu/datadesign/classsource/repo/Default.aspx
−
nesting controls
 
  
−
Datasource Controls can probably handle up to 70% of your data binding needs but they do have drawbacks. Consider the cheese database which uses an SQL view to join Cheese with Region, Consistency, and MilkType. Of course SQL view don't support updating and can lead to some bad data binding. we can fix a few of these problem with stored procedures.
+
http://iam.colum.edu/datadesign/gbrowser.php?file=/classsource/repo/Default.aspx.cs
  
−
Simple filter Demo in class
+
<syntaxhighlight lang="csharp">
 +
ICheeseRepo db = new TestCheeseRepository();
 +
        gv1.DataSource = db.GetCheeses();
 +
        gv1.DataBind();
 +
</syntaxhighlight>
  
−
GridView Details View Master Child Relationship
 
  
  
−
http://iam.colum.edu/dd/classsource/data/CheeseDataBindingFull.aspx
+
You can add LINQ helpers to the class
−
[http://iam.colum.edu/dd/gbrowser.php?file=/classsource/Data/CheeseDataBindingFull1.aspx source]
+
<syntaxhighlight lang="csharp">
 +
/// <summary>
 +
    /// Cheese Class for Our Repo
 +
    /// </summary>
 +
    [Table(Name = "Cheese")]
 +
    public class Cheese
 +
    {
 +
        [Column(IsPrimaryKey = true, IsDbGenerated = true, AutoSync = AutoSync.OnInsert)]
 +
        public int CheeseID { get; set; }
 +
        [Column]
 +
        public string CheeseName { get; set; }
 +
        [Column]
 +
        public string CheeseDescription { get; set; }
 +
    }
 +
</syntaxhighlight>
  
−
==Stored Procedures==
+
and then create a new cheese repo
  
−
http://iam.colum.edu/dd/classsource/data/sproc/sprocADO.aspx
+
and update your repo initialization
  
−
==Cheese browser assignment==
+
<syntaxhighlight lang="csharp">
 +
ICheeseRepo db = new CheeseRepository(ConfigurationManager.ConnectionStrings["cheeseConnectionString"].ToString());
 +
        gv1.DataSource = db.GetCheeses();
 +
        gv1.DataBind();
 +
</syntaxhighlight>
  
−
Make a creative cheese browser from that tables in you db. Use a view to join that data from multiple tables..
+
LINQ classes in MVC must use the entire namespace
 +
<syntaxhighlight lang="csharp">
 +
/// <summary>
 +
    /// Cheese Class for Our Repo
 +
    /// </summary>
 +
    [System.Data.Linq.Mapping.Table(Name = "Cheese")]
 +
    public class Cheese
 +
    {
 +
        [System.Data.Linq.Mapping.Column(IsPrimaryKey = true, IsDbGenerated = true, AutoSync = AutoSync.OnInsert)]
 +
        public int CheeseID { get; set; }
 +
        [System.Data.Linq.Mapping.Column]
 +
        public string CheeseName { get; set; }
 +
        [System.Data.Linq.Mapping.Column]
 +
        public string CheeseDescription { get; set; }
 +
    }
 +
</syntaxhighlight>
  
−
Here's and example of a simple cheese shop browser app.
+
==Homework==
  
−
http://iam.colum.edu/dd/classsource/class8/CheeseShop/CheeseShop1.aspx
+
Use the repo pattern to create a repo for you own class. The the class should map to a table in your database. The repo should be able to show items in you db, add items and remove items.  
  
−
==Homework==
+
Add the repo to your Web from site and your MVC site. The repose should be able to list items from the DB. Either the MVC site or the WebForms site should be able to add and delete items.
−
Make a creative cheese browser from that tables in you db. Use a view to join that data from multiple tables..
+
I'll give 1 pt extra for updating items and 1 pt for adding/deleting in MVC and Web Forms.

Latest revision as of 03:20, 9 February 2016


Repo Pattern

Definition from P of EE http://martinfowler.com/eaaCatalog/repository.html MSDN The Repository Pattern

The repository pattern is a nice way to abstract data fetching logic and easily separate concerns from different layers of your app. It allows of to quickly refactor and swap repos.

First we can start with the cheese definition 

 public class Cheese
    {
        
        public int CheeseID { get; set; }
        
        public string CheeseName { get; set; }
        
        public string CheeseDescription { get; set; }
    }

Then interface for the repo 

public interface IRepository<T>
    {
        T GetById(int id);
        List<T> GetItems();
        void Add(T entity);
        void Remove(T entity);
    }

Now we want to expand the interface definition to cheeses 

/// <summary>
    /// ICheeseRepo Changes the type of the Generic Repo To Cheese
    /// </summary>
    public interface ICheeseRepo : IRepository<Cheese>
    {
        List<Cheese> GetItems();
        List<Cheese> GetCheeses();  //New Method To Get Cheeses
        //May want to expand the definition to get cheese by name
        //Cheese GetByName(string name)
    }

Finally the repo interface can then be implemented like this 

public class TestCheeseRepository : ICheeseRepo
    {

        //could grab these from the Application Object
        private static List<Cheese> fakeCheeses =
            new List<Cheese> { new Cheese { CheeseID=1, CheeseName="test1", CheeseDescription = "test desc 1" },
                new Cheese { CheeseID=2, CheeseName="test2", CheeseDescription = "test desc 2" },
                new Cheese { CheeseID=2, CheeseName="test3", CheeseDescription = "test desc 3" }
            };


        #region ICheeseRepo Members
        public List<Cheese> GetItems()
        {
            return GetCheeses();
        }


        public List<Cheese> GetCheeses()
        {
            return fakeCheeses.ToList();
        }

        #endregion

        #region IRepository<Cheese> Members

        public Cheese GetById(int id)
        {
            //linq statement to find cheese by ID
            var currentCheese = from c in fakeCheeses where c.CheeseID == id select c;
            return currentCheese.FirstOrDefault();
        }

        public void Add(Cheese entity)
        {
            fakeCheeses.Add(entity);
        }

        public void Remove(Cheese entity)
        {
            fakeCheeses.Remove(entity);
        }

        #endregion

        //added statement to find cheese by name
        public Cheese GetByName(string name)
        {
            //linq statement to find cheese by name
            var currentCheese = from c in fakeCheeses where c.CheeseName == name select c;
            return currentCheese.FirstOrDefault();
        }
    }

Link to the implememtation http://iam.colum.edu/datadesign/gbrowser.php?file=/App_code/Repo/CheeseRepo.cs

Now to use the Repo

http://iam.colum.edu/datadesign/classsource/repo/Default.aspx

http://iam.colum.edu/datadesign/gbrowser.php?file=/classsource/repo/Default.aspx.cs 

ICheeseRepo db = new TestCheeseRepository();
        gv1.DataSource = db.GetCheeses();
        gv1.DataBind();


You can add LINQ helpers to the class 

/// <summary>
    /// Cheese Class for Our Repo
    /// </summary>
    [Table(Name = "Cheese")]
    public class Cheese
    {
        [Column(IsPrimaryKey = true, IsDbGenerated = true, AutoSync = AutoSync.OnInsert)]
        public int CheeseID { get; set; }
        [Column]
        public string CheeseName { get; set; }
        [Column]
        public string CheeseDescription { get; set; }
    }

and then create a new cheese repo

and update your repo initialization 

ICheeseRepo db = new CheeseRepository(ConfigurationManager.ConnectionStrings["cheeseConnectionString"].ToString()); 
        gv1.DataSource = db.GetCheeses();
        gv1.DataBind();

LINQ classes in MVC must use the entire namespace 

/// <summary>
    /// Cheese Class for Our Repo
    /// </summary>
    [System.Data.Linq.Mapping.Table(Name = "Cheese")]
    public class Cheese
    {
        [System.Data.Linq.Mapping.Column(IsPrimaryKey = true, IsDbGenerated = true, AutoSync = AutoSync.OnInsert)]
        public int CheeseID { get; set; }
        [System.Data.Linq.Mapping.Column]
        public string CheeseName { get; set; }
        [System.Data.Linq.Mapping.Column]
        public string CheeseDescription { get; set; }
    }

Homework

Use the repo pattern to create a repo for you own class. The the class should map to a table in your database. The repo should be able to show items in you db, add items and remove items.

Add the repo to your Web from site and your MVC site. The repose should be able to list items from the DB. Either the MVC site or the WebForms site should be able to add and delete items. I'll give 1 pt extra for updating items and 1 pt for adding/deleting in MVC and Web Forms.

Retrieved from "http://imamp.colum.edu/mediawiki/index.php?title=DD_Class9&oldid=22482"