通过接口实现适用于SqlServer和MySql的SqlHelper

SqlHelper

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SqlHelper
{
    class DBHelper
    {
        private static readonly string connStr = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;
        public static IDbConnection CreateConnection()
        {
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();
            return conn;
        }

        public static int ExecuteNonQuery(IDbConnection conn, string sql, Dictionary<string, object> parameters)
        {
            using (IDbCommand cmd = conn.CreateCommand())
            {
                cmd.CommandText = sql;
                foreach (KeyValuePair<string, object> kv in parameters)
                {
                    IDataParameter parameter = cmd.CreateParameter();
                    parameter.ParameterName = kv.Key;
                    parameter.Value = kv.Value;
                    cmd.Parameters.Add(parameter);
                }
                return cmd.ExecuteNonQuery();
            }
        }

        public static int ExecuteNonQuery(string sql, Dictionary<string, object> parameters)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return ExecuteNonQuery(conn, sql, parameters);
            }
        }

        public static object ExecuteScalar(IDbConnection conn, string sql, Dictionary<string, object> parameters)
        {
            using (IDbCommand cmd = conn.CreateCommand())
            {
                cmd.CommandText = sql;
                foreach (KeyValuePair<string, object> kv in parameters)
                {
                    IDataParameter parameter = cmd.CreateParameter();
                    parameter.ParameterName = kv.Key;
                    parameter.Value = kv.Value;
                    cmd.Parameters.Add(parameter);
                }
                return cmd.ExecuteScalar();
            }
        }

        public static object ExecuteScalar(string sql, Dictionary<string, object> parameters)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return ExecuteScalar(conn, sql, parameters);
            }
        }

        public static DataTable ExecuteQuery(IDbConnection conn, string sql, Dictionary<string, object> parameters)
        {
            DataTable table = new DataTable();
            using (IDbCommand cmd = conn.CreateCommand())
            {
                cmd.CommandText = sql;
                foreach (KeyValuePair<string, object> kv in parameters)
                {
                    IDataParameter parameter = cmd.CreateParameter();
                    parameter.ParameterName = kv.Key;
                    parameter.Value = kv.Value;
                    cmd.Parameters.Add(parameter);
                } 
                using (IDataReader reader = cmd.ExecuteReader())
                {
                    table.Load(reader);
                }
                return table;
            }
        }

        public static DataTable ExecuteQuery(string sql, Dictionary<string, object> parameters)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return ExecuteQuery(conn, sql, parameters);
            }
        }
    }
}