Csharp/CSharp Tutorial/ADO.Net/SqlCommand Delete

Delete data using sql statements

using System;
using System.Data;
using System.Data.SqlClient;
class MainClass
{
  static void Main(string[] args)
  {
    SqlConnection MyConnection = new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
    MyConnection.Open();
    String MyString = "DELETE Employee";
    SqlCommand MyCmd = new SqlCommand(MyString, MyConnection);
    MyCmd.ExecuteScalar();
    MyConnection.Close();
  }
}

Deleting Data

using System;
using System.Data;
using System.Data.SqlClient; 
using System.Collections.Generic;
using System.Text;
  class Program
  {
    static void Main(string[] args)
    {
      SqlConnection thisConnection = new SqlConnection(
                @"Data Source=.\SQLEXPRESS;" +
                @"AttachDbFilename="NORTHWND.MDF";" +
                @"Integrated Security=True;Connect Timeout=30;User Instance=true");
      SqlDataAdapter thisAdapter = new SqlDataAdapter("SELECT CustomerID, CompanyName FROM Customers", thisConnection);
      SqlCommandBuilder thisBuilder = new SqlCommandBuilder(thisAdapter);
      DataSet thisDataSet = new DataSet();
      thisAdapter.Fill(thisDataSet, "Customers");
      Console.WriteLine("# rows before change: {0}",thisDataSet.Tables["Customers"].Rows.Count);
      DataColumn[] keys = new DataColumn[1];
      keys[0] = thisDataSet.Tables["Customers"].Columns["CustomerID"];
      thisDataSet.Tables["Customers"].PrimaryKey = keys;
      DataRow findRow = thisDataSet.Tables["Customers"].Rows.Find("1");
      findRow.Delete();
      int rowsAffected = thisAdapter.Update(thisDataSet, "Customers");
            Console.WriteLine("Deleted {0} rows.", rowsAffected);
      Console.WriteLine(thisDataSet.Tables["Customers"].Rows.Count);
      thisConnection.Close();
    }
  }

Execute nonquery to delete a record (row)

using System;
using System.Data;
using System.Data.SqlClient;
class MainClass
{
   static void Main()
   {
      SqlConnection conn = new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
      string sqlqry = @"select count(*) from employee ";
      string sqlins = @"insert into employee (firstname,lastname)values("Z", "Z")";
      string sqldel = @"delete from employee  where firstname = "Z" and lastname = "Z"";
      SqlCommand cmdqry = new SqlCommand(sqlqry, conn);
      SqlCommand cmdnon = new SqlCommand(sqlins, conn);
      try
      {
         conn.Open();
         Console.WriteLine("Before INSERT: Number of employees {0}\n", cmdqry.ExecuteScalar());
         Console.WriteLine("Executing statement {0}", cmdnon.rumandText);
         cmdnon.ExecuteNonQuery();
         Console.WriteLine("After INSERT: Number of employees {0}\n", cmdqry.ExecuteScalar());
         cmdnon.rumandText = sqldel;
         Console.WriteLine("Executing statement {0}", cmdnon.rumandText);
         cmdnon.ExecuteNonQuery();
         Console.WriteLine("After DELETE: Number of employees {0}\n", cmdqry.ExecuteScalar());
      }
      catch (SqlException ex)
      {
         Console.WriteLine(ex.ToString());
      }
      finally
      {
         conn.Close();
         Console.WriteLine("Connection Closed.");
      }
   }
}