Connnection Maneger(Use in SQL and Access Data base Connection)

To create a Class in Class Library File and write this code in Class :-

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Configuration;

using System.Data;

using System.Data.SqlClient;

//Add redfrence-System.Configuration

namespace CommCon

{

    public class ConnectionManager

    {

        readonly SqlConnection _conn;

        SqlCommand _cmd;

        SqlDataAdapter _adap;

        public ConnectionManager()

        {

            _conn = new SqlConnection(GetConnectionString());

            _cmd = new SqlCommand();

            _adap = new SqlDataAdapter();

        }

        public static string GetConnectionString()

        {

            return ConfigurationManager.ConnectionStrings["dbConnection"].ConnectionString;

        }

        public static SqlConnection CreateConnection()

        {

            SqlConnection conn = new SqlConnection { ConnectionString = GetConnectionString() };

            return (conn);

        }

        public static SqlCommand CreateCommand()

        {

            SqlConnection conn = new SqlConnection();

            SqlCommand cmd = new SqlCommand();

            conn.ConnectionString = GetConnectionString();

            cmd.Connection = conn;

            return cmd;

        }

        public DataSet ExecuteQuery(string query, string tableName)

        {

            _adap = new SqlDataAdapter(query, _conn);

            _conn.Open();

            DataSet ds = new DataSet();

            _adap.Fill(ds, tableName);

            _conn.Close();

            return ds;

        }

        public DataSet ExecuteQuery(SqlCommand cmd, string tableName)

        {

            _conn.Open();

            cmd.Connection = _conn;

            _adap = new SqlDataAdapter(cmd);

            DataSet ds = new DataSet();

            _adap.Fill(ds, tableName);

            _conn.Close();

            return ds;

        }

        public void ExecuteInsert(SqlCommand cmdInsert)

        {

            _conn.Open();

            cmdInsert.Connection = _conn;

            cmdInsert.ExecuteNonQuery();

            _conn.Close();

        }

        public void ExecuteInsert(string query)

        {

            _cmd = new SqlCommand(query, _conn);

            _conn.Open();

            _cmd.ExecuteNonQuery();

            _conn.Close();

        }

    }

}

Add app.config file and write this code :

For Sql Server :

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

  <connectionStrings >

    <add name="dbConnection" connectionString ="Data Source=.;Initial Catalog=Falcon_Retail;Integrated Security=True"/>

  </connectionStrings>

  <appSettings>

    <add key="SecurityKey" value="Shashi"/>

  </appSettings>

</configuration>

For Access: 

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

  <connectionStrings >

     <add name="dbConnection" connectionString ="Provider=Microsoft.jet.OLEDB.4.0;Data source=D:\\BHK\\Security Service.mdb;persist security info=false;jet oledb:database password=*******"/>

  </connectionStrings>

  <appSettings>

    <add key="SecurityKey" value="Shashi Ranjan"/>

  </appSettings>

</configuration>