Create table and populate data

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using System;
using System.Data;
using System.Data.OleDb;

public class Create {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();
   OleDbCommand cmd = con.CreateCommand();

   cmd.CommandText = "CREATE TABLE Customer (CustomerID "
       + "CHAR(4), CustomerName VARCHAR(25), Address "
       + "VARCHAR(25), BalanceDue DECIMAL)";
   cmd.ExecuteNonQuery();
   cmd.CommandText = "INSERT INTO Customer VALUES (1234,'F F','22 First St.',67.00)";
   cmd.ExecuteNonQuery();
   cmd.CommandText = "INSERT INTO Customer VALUES (5678,'D D','33 Second St.',130.95)";
   cmd.ExecuteNonQuery();
   cmd.CommandText = "INSERT INTO Customer VALUES (4321,'M M','44 Third St.',0)";
   cmd.ExecuteNonQuery();
   cmd.CommandText = "INSERT INTO Customer VALUES (8765,'C C','55 Fourth St.', 0)";
   cmd.ExecuteNonQuery();

   con.Close();
 }
} 

           
          


Delete database records through OleDbCommand and verify the results

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using System;
using System.Data;
using System.Data.OleDb;

public class ExtractInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the Sales database");
   OleDbCommand cmd = con.CreateCommand();
   
   cmd.CommandText ="DELETE FROM Employee WHERE ID = 01"; 
   cmd.ExecuteNonQuery();
   cmd.CommandText = "SELECT First_Name FROM Employee";
   OleDbDataReader reader = cmd.ExecuteReader();
   Console.WriteLine();
   while(reader.Read()) 
     Console.WriteLine(reader.GetString(0)); 
   reader.Close();

   con.Close();
 }
}
           
          


Between certain dates

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using System;
using System.Data;
using System.Data.OleDb;

public class ExtractInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the Sales database");
   OleDbCommand cmd = con.CreateCommand();
   
   cmd.CommandText =  "SELECT OrderNumber FROM Orders "
             + "WHERE OrderDate BETWEEN #4/1/99# AND #4/30/99#";
   OleDbDataReader reader = cmd.ExecuteReader();
   Console.WriteLine();
   Console.WriteLine
      ("   Order numbers of orders from 4/1/99 to 4/30/99");
   while(reader.Read())
     Console.WriteLine(reader.GetString(0)); 
   reader.Close();




   con.Close();
 }
}
           
          


Get count value from a select query

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using System;
using System.Data;
using System.Data.OleDb;

public class DatabaseInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the database");

   OleDbCommand command = con.CreateCommand();
   command.CommandText = "SELECT COUNT(*) FROM Employee";
   Console.WriteLine("Number of Employee rows: {0}",(int)command.ExecuteScalar());
   con.Close();
 }
}
 
           
          


Get max column value

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using System;
using System.Data;
using System.Data.OleDb;

public class DatabaseInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the database");

   OleDbCommand command = con.CreateCommand();
   command.CommandText ="SELECT MAX(Salary) FROM Employee";
   Console.WriteLine("Max of salary: {0:C}",(decimal)command.ExecuteScalar());
   con.Close();
 }
}
 

           
          


Get column average

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using System;
using System.Data;
using System.Data.OleDb;

public class DatabaseInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the database");

   OleDbCommand command = con.CreateCommand();
   command.CommandText = "SELECT AVG(Salary) FROM Employee";
   Console.WriteLine("Average of salary: {0:C}",(decimal)command.ExecuteScalar());


   con.Close();
 }
}
 
           
          


Execute aggregate function: sum

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using System;
using System.Data;
using System.Data.OleDb;

public class DatabaseInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the database");

   OleDbCommand command = con.CreateCommand();
   command.CommandText ="SELECT SUM(salary) FROM Employee";
   Console.WriteLine("Sum of salary: {0:C}",(decimal)command.ExecuteScalar());


   con.Close();
 }
}