如何在web.config中建立公用的的数据库连接

<configuration>
    <!-- application specific settings -->
    <appSettings>
        <add key=ConnectionString value=server=localhost;uid=sa;pwd=;database=store />
    </appSettings>
<configuration>

public SqlDataReader GetReviews(int PRoductID) {

    // 创建Connection和Command对象实例
    SqlConnection myConnection = new SqlConnection(ConfigurationSettings.AppSettings[ConnectionString]);
    SqlCommand myCommand = new SqlCommand(ReviewsList, myConnection);

    myCommand.CommandType = CommandType.StoredProcedure;

    // 参数
    SqlParameter parameterProductID = new SqlParameter(@ProductID, SqlDbType.Int, 4);
    parameterProductID.Value = productID;
    myCommand.Parameters.Add(parameterProductID);

    // 执行
    myConnection.Open();
    SqlDataReader result = myCommand.ExecuteReader(CommandBehavior.CloseConnection);

    // 返回结果
    return result;
数据库连接;return true>