LINQ: Perform CRUD operations by using ADO.NET Entity FrameWork

Software Requirements: Visual Studio (3.5/4.0), SQL Server 2005

Step1:Create DataBase In SQL Server

Create Table StockMaster :Query

Create table StockMaster
(
ItemCode varchar(5) NOT NULL PRIMARY KEY,
ItemName varchar(50) NOT NULL,
Stock int,
float float

)

Step2:Create New Application 

Start Microsoft Visual Studio => File=> New=> Project => Choose Language(c#)=> Choose Application(indow Application )=>0k

Step3:  Create Entity data model  from the existing database connection

Solution Explorer =>right click on project => Add  => New Item. Select the Data Template => ADO.NET Entity Data Model and click Add.

The Entity Data Model Wizard appears. Choose ‘Generate From Database’ and click Next 

You have to now choose your DataBase Connection.

Our Entity Connection Settings will be stored in the App.Config file as ‘eguardEntities'. You can change the name to anything else you want. Click Next

choose the Database Objects You want to include in your Entity Data Model (EDM).The checkbox ‘Pluralize or singularize generated object names’ gives us the ability to pluralize or singularize object names. This is new to EF 4.0 and is a welcome change, as in EF 3.5, not being able to rename/pluralize objects in the model, caused a great deal of confusion.Click Finish to complete the wizard.

The .edmx  design looks like.

Step4: Perform CRUD operations by using EDM

Code  Description 

Create Instance of DataContext

eguardEntities EguardEntities=new eguardEntities ();

Get Data from the DataBase through Entity Framework

public  object   GetStockMaster()
        {
            var v=from sm in EguardEntities .StockMasters 
                  select sm;
            return v;
       }

GetStockMaster() Method returns Object datatype. object  binds to Datagridview 

 var V=    StockMaster.GetStockMaster();
           stkMaterGridview.DataSource = V;

Delete records From StockMaster through Entity Framework

SaveChanges() method on the context to reflect the changes back to database.

public bool DeleteStockMaster(string ItemCodes)
       {
           try
           {
          foreach(var sm in EguardEntities.StockMasters.Where(p1=>p1.ItemCode.Equals(ItemCodes)))
               {
                   EguardEntities.DeleteObject(sm);
               }
                EguardEntities.SaveChanges();
               return true;
 
           }
           catch(Exception ex)
           {
               return false;
           }
 
       }
 

Insert StockMaster through entity framework

Entity in the entity model which is StockMaster. Create instance of StockMaster.Then we can set values properties like ItemCode, ItemName, Rate, Stock.I have been set these value statically. You can set these value dynamically.

               StockMaster stockmaster = new StockMaster();
               stockmaster.ItemCode = "rg";
               stockmaster.ItemName = "Register";
               stockmaster.Rate = 20;
               stockmaster.Stock = 12;

ObjectContext itself provides an AddObject() method which can be used as

AddObject("StockMasters",stockmaster);

SaveChanges() method of the context to reflect the changes back to the database. It returns Integer value.

int numberOfAffectedRows = EguardEntities.SaveChanges();

        public int  InsertStockMaster(
{
           try
           {
               StockMaster
stockmaster = new StockMaster();
               stockmaster.ItemCode = "rg";
               stockmaster.ItemName = "Register";
               stockmaster.Rate = 20;
               stockmaster.Stock = 12;
            
 
               //er.AddToOrderDetails(o);

               EguardEntities.AddObject("StockMasters", stockmaster);
               int numberOfAffectedRows = EguardEntities.SaveChanges();
               if(numberOfAffectedRows>0)
               {
                   return numberOfAffectedRows;
               }
               else
                   return 0;
           }
 
           catch(Exception ex)
           {
               return 0;
           }
 
 
 
 
 
       }

Perform Update Operations Using Entity Framework

  varv = (from stkmaster in
EguardEntities.StockMasters where
stkmaster.ItemCode.Equals(ItemCodes) select
stkmaster).ToList<StockMaster>();

This LINQ query returns record  which save in v variable. Before Update any record  We have to delete the object using deleteObject and then save these changes in database by calling SaveChanges() method. 

EguardEntities.DeleteObject(stockMaster);

       public void UpdateStockMaster(stringItemCodes)

       {         var v = (from stkmaster in EguardEntities.StockMasters where stkmaster.ItemCode.Equals(ItemCodes) select
stkmaster).ToList<StockMaster>();
foreach (StockMaster stockMaster  in v)
{
  EguardEntities.DeleteObject(stockMaster);
  EguardEntities.SaveChanges();
  stockMaster.ItemName ="Ups";
  EguardEntities.AddObject("StockMasters", stockMaster);
  EguardEntities.SaveChanges();
}
   }
   }
}