Simple utility functions for connecting to database

DbProvider.cs

using System.Data;
using System.Configuration;
using System.Data.Common;
using System.Data.Linq;

namespace Dapper
{
    /// <summary>
    /// Utility functions for connecting to database
    /// </summary>
    public static class DbProvider
    {
        /// <summary>
        /// AppSetting key specifying ConnectionString name used as Default Connection
        /// </summary>
        private static string DefaultConnection { get { return ConfigurationManager.AppSettings["DefaultConnection"]; } }

        /// <summary>
        /// Creates a generic connection to the DefaultConnection
        /// </summary>
        /// <param name="Open">To open the connection by default</param>
        /// <returns>System.Data.IDbConnection to DB specified in DefaultConnection</returns>
        public static IDbConnection GetConnection(bool Open = false)
        {
            return GetConnection(DefaultConnection, Open);
        }

        /// <summary>
        /// Creates a generic connection to the specified ConnectionString Name
        /// </summary>
        /// <param name="ConnectionStringName">Name of the ConnectionString</param>
        /// <param name="Open">To open the connection by default</param>
        /// <returns>System.Data.IDbConnection to DB specified in specified ConnectionString name</returns>
        public static IDbConnection GetConnection(string ConnectionStringName, bool Open = false)
        {
            IDbConnection con = GetConnection(
                ConfigurationManager.ConnectionStrings[ConnectionStringName].ProviderName,
                ConfigurationManager.ConnectionStrings[ConnectionStringName].ConnectionString
                );
            if(Open)
                con.Open();
            return con;
        }

        /// <summary>
        /// Creates a specified provider connection for given ConnectionString
        /// </summary>
        /// <param name="ProviderName">Provider name of database specified in the connection string</param>
        /// <param name="ConnectionString">ConnectionString to database</param>
        /// <returns>System.Data.IDbConnection to DB specified in specified ConnectionString</returns>
        private static IDbConnection GetConnection(string ProviderName, string ConnectionString)
        {
            var provider = DbProviderFactories.GetFactory(ProviderName);
            IDbConnection con = provider.CreateConnection();
            if (!string.IsNullOrEmpty(ConnectionString))
            {
                con.ConnectionString = ConnectionString;
            }
            return con;
        }

        /// <summary>
        /// Creates a generic command to the specified ConnectionString name
        /// </summary>
        /// <param name="SetConnection">To set default connection string</param>
        /// <param name="Open">To open the connection by default</param>
        /// <returns>System.Data.IDbCommand for DefaultConnection</returns>
        public static IDbCommand GetCommand(bool SetConnection = true, bool Open = false)
        {
            return GetCommand(DefaultConnection, SetConnection, Open);
        }

        /// <summary>
        /// Get a generic command to the specified ConnectionString Name
        /// </summary>
        /// <param name="ConnectionStringName">Name of the ConnectionString</param>
        /// <param name="SetConnection">To set default connection string</param>
        /// <param name="Open">To open the connection by default</param>
        /// <returns>System.Data.IDbCommand for DB specified in given ConnectionString Name</returns>
        public static IDbCommand GetCommand(string ConnectionStringName, bool SetConnection = true, bool Open = false)
        {
            var connectionStr = ConfigurationManager.ConnectionStrings;
            IDbCommand cmd = DbProviderFactories.GetFactory(connectionStr[ConnectionStringName].ProviderName).CreateCommand();
            if (SetConnection)
            {
                cmd.Connection = GetConnection(
                    ConfigurationManager.ConnectionStrings[ConnectionStringName].ProviderName,
                    ConfigurationManager.ConnectionStrings[ConnectionStringName].ConnectionString
                    );
                if(Open)
                    cmd.Connection.Open();
            }
            return cmd;
        }

        /// <summary>
        /// Creates a Linq DataContext to default database
        /// </summary>
        /// <returns>System.Data.Linq.DataContext to default database</returns>
        public static DataContext GetDataContext()
        {
            return GetDataContext(DefaultConnection);
        }

        /// <summary>
        /// Creates a Linq DataContext to database specified in given ConnectionString name
        /// </summary>
        /// <param name="ConnectionStringName">Name of the ConnectionString</param>
        /// <returns>System.Data.Linq.DataContext to the DB in given ConnectionString Name</returns>
        public static DataContext GetDataContext(string ConnectionStringName)
        {
            return new DataContext(GetConnection(ConnectionStringName));
        }
    }
}

Define your ConnectionStrings in web.config and specify default connection to be used in 'DefaultConnection' AppSetting.

<configuration>
 <connectionStrings>
    <clear/>
    <add name="MsSql" connectionString="Server=.;Database=testdb;User Id=sa;Password=****;" 
         providerName="System.Data.SqlClient" />
  </connectionStrings>
    <add name="MySql" connectionString="Database=MyDb;Server=localhost;Username=root;Password=****;" 
         providerName="MySql.Data.MySqlClient" />
  </connectionStrings>
  <appSettings>
    <add key="DefaultConnection" value="MsSql" />

Then connect to default database as

using(var con = DbProvider.GetConnection())
{
  return con.Query<MyModel>(strQuery, new { d="dynamicParams" });
}

or to another database as

using(var con = DbProvider.GetConnection("MySql"))
{
  return con.Query<MyModel>(strQuery, new { d="dynamicParams" });
}