Difference between revisions of "DD Class9"
esse quam videri
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[[Category:Data Design]] | [[Category:Data Design]] | ||
| − | == | + | ==Repo Pattern== |
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| − | + | Definition from P of EE http://martinfowler.com/eaaCatalog/repository.html | |
| − | [http:// | + | 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. | |
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| − | + | First we can start with the cheese definition | |
| − | + | <syntaxhighlight lang="csharp"> | |
| + | public class Cheese | ||
| + | { | ||
| + | |||
| + | 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 | ||
| + | { | ||
| − | + | //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" } | |
| − | + | }; | |
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| − | + | #region ICheeseRepo Members | |
| − | + | public List<Cheese> GetItems() | |
| − | + | { | |
| − | + | return GetCheeses(); | |
| − | + | } | |
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| − | + | public List<Cheese> GetCheeses() | |
| + | { | ||
| + | return fakeCheeses.ToList(); | ||
| + | } | ||
| − | + | #endregion | |
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| − | + | #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(); | ||
| + | } | ||
| + | } | ||
| + | </syntaxhighlight> | ||
| − | + | Link to the implememtation http://iam.colum.edu/datadesign/gbrowser.php?file=/App_code/Repo/CheeseRepo.cs | |
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| − | + | Now to use the Repo | |
| − | + | http://iam.colum.edu/datadesign/classsource/repo/Default.aspx | |
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| + | http://iam.colum.edu/datadesign/gbrowser.php?file=/classsource/repo/Default.aspx.cs | ||
| − | + | <syntaxhighlight lang="csharp"> | |
| − | + | ICheeseRepo db = new TestCheeseRepository(); | |
| − | + | gv1.DataSource = db.GetCheeses(); | |
| − | + | gv1.DataBind(); | |
| − | + | </syntaxhighlight> | |
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| − | + | You can add LINQ helpers to the class | |
| − | < | + | <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> | ||
| − | + | and then create a new cheese repo | |
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| − | + | and update your repo initialization | |
| − | < | + | <syntaxhighlight lang="csharp"> |
| − | + | ICheeseRepo db = new CheeseRepository(ConfigurationManager.ConnectionStrings["cheeseConnectionString"].ToString()); | |
| − | + | gv1.DataSource = db.GetCheeses(); | |
| − | + | gv1.DataBind(); | |
| − | + | </syntaxhighlight> | |
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| − | + | 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> | |
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==Homework== | ==Homework== | ||
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| − | + | 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. | ||
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.
