.NET Core Dapper操作mysql数据库的实现方法

时间:2022-08-23 00:14:47

前言

现在ORM盛行,市面上已经出现了N款不同的ORM套餐了。今天,我们不谈EF,也不聊神马黑马,就说说 Dapper。如何在.NET Core中使用Dapper操作Mysql数据库呢,让我们跟随镜头(手动下翻)一看究竟。

配置篇

俗话说得好,欲要善其事必先利其器。首先,我们要引入MySql.Data 的Nuget包。有人可能出现了黑人脸,怎么引入。也罢,看在你骨骼惊奇的份上,我就告诉你,两种方式:

第一种方式

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Install-Package MySql.Data -Version 8.0.15

复制上面命令行 在程序包管理控制台中执行,什么?你不知道什么是程序包管理控制台?OMG,也罢,看在你骨骼惊奇的份上,我就告诉你

手点路径:工具 → NuGet包管理器 → 程序包管理控制台 

.NET Core Dapper操作mysql数据库的实现方法

第二种方式

手点路径:右键你需要引入包的项目的依赖项 → 管理NuGet程序包  → 浏览里面输入 MySql.Data

.NET Core Dapper操作mysql数据库的实现方法

.NET Core Dapper操作mysql数据库的实现方法

直接安装即可,因为我已经安装过了,所以这里是卸载或者更新

同样的方式你需要引入:

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Microsoft.AspNetCore.All
MySql.Data.EntityFrameworkCore、
Dapper
Microsoft.Extensions.Configuration.Abstractions
Microsoft.Extensions.Configuration.FileExtensions
Microsoft.Extensions.Configuration.Json

教学篇

玩儿过.NET Core 的都知道配置文件我们一般都放在appsettings.json 文件中,但是有个问题,如果我们使用数据库连接字符串,直接存放明文的user name和password,真的安全吗?这里我们不对安全性做讨论,我们在连接字符串中 用占位符控制我们的多数据库情况,然后用userName以及passWord充当我们密码(后面会被替换掉),所以看起来是这个样子:

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"ConnectionStrings": {
 "DefaultConnection": "server=服务器;port=端口号;database=regatta{0};SslMode=None;uid=userName;pwd=passWord;Allow User Variables=true"
},

接下来,我们新建一个BaseRepository 用于读取Configuration,以及设置MySqlConnection:

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public class BaseRepository : IDisposable
  {
    public static IConfigurationRoot Configuration { get; set; }
 
    private MySqlConnection conn;
 
    public MySqlConnection GetMySqlConnection(int regattaId = 0, bool open = true,
      bool convertZeroDatetime = false, bool allowZeroDatetime = false)
    {
      IConfigurationBuilder builder = new ConfigurationBuilder()
        .SetBasePath(Directory.GetCurrentDirectory())
        .AddJsonFile("appsettings.json");
 
      Configuration = builder.Build();
      
 
      string cs = Configuration.GetConnectionString("DefaultConnection");
      cs = regattaId == 0 ? string.Format(cs, string.Empty) : string.Format(cs, "_" + regattaId.ToString());
 
      cs = cs.Replace("userName", "真正的账号").Replace("passWord", "真正的密码");
      var csb = new MySqlConnectionStringBuilder(cs)
      {
        AllowZeroDateTime = allowZeroDatetime,
        ConvertZeroDateTime = convertZeroDatetime
      };
      conn = new MySqlConnection(csb.ConnectionString);
      return conn;
    }
public void Dispose()
{
if (conn != null && conn.State != System.Data.ConnectionState.Closed)
{
conn.Close();
}
}
 
}

好了,创建完毕,我们该如何使用呢,比方说 现在有个CrewManagerRepository类用于操作数据库,我们只需要让此类 继承BaseRepository , 示例如下

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/// <summary>
  /// 根据赛事Id、用户Id获取用户基本信息
  /// </summary>
  /// <param name="regattaId">赛事Id</param>
  /// <param name="userId">用户Id</param>
  /// <returns></returns>
  public async Task<实体对象> FindUserByAccount(int regattaId, int userId)
  {
    try
    {
      var cmdText =
        @"select b.id_number as IdentifierId,b.isvalid as Isvalid,a.name as Name,a.userid as InternalId,a.sex as Sexual,a.sex as SexTypeId,a.age as Age,
              c.isprofessional as IsProfessional,c.role_type as RoleTypeId,a.weight as Weight,a.height as Height, a.phone as PhoneNumber,a.thumb_image as ThubmnailImage,
              a.image as Image,c.athlete_id as AthleteId from 表1 a left join 表2 b on a.userid=b.id
              left join 表3 c on b.id=c.centralid where a.userid=@userId;";
        //此处可以根据传入的regattaId访问不同的数据库
      using (var conn = GetMySqlConnection(regattaId))
      {
        if (conn.State == ConnectionState.Closed)
        {
          await conn.OpenAsync();
        }
 
        var memberModel = conn
          .Query<实体对象>(cmdText, new { userId = userId }, commandType: CommandType.Text)
          .FirstOrDefault();
        return memberModel ?? new MemberDetail();
      }
    }
    catch (Exception ex)
    {
      _logger.LogError(ex, "FindUserByAccount by Id Failed!");
      throw;
    }
 
 
  }

那有同学可能有黑人脸出现了,如果需要事务呢(露出嘴角的微笑)?

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public async Task<bool> DeleteXXX(int regattaId, int id, int userId)
    {
      var result = false;
      using (var conn = GetMySqlConnection(regattaId))
      {
        if (conn.State == ConnectionState.Closed)
        {
          await conn.OpenAsync();
        }
 
        using (var transaction = conn.BeginTransaction())
        {
          try
          {
            const string sqlDelClub =
              @"delete from 表名 where 字段1=@clubId;
               delete from 表名2 where 字段2=@clubId;
               delete from 表名3 where 字段3=@userId and clubinfo_id=@clubId;";
 
            await conn.QueryAsync(sqlDelClub, new
            {
              clubId = id,
              userId = userId,
            }, commandType: CommandType.Text);
 
            transaction.Commit();
 
            result = true;
          }
          catch (Exception e)
          {
            Console.WriteLine(e);
            transaction.Rollback();
            result = false;
            throw;
          }
        }
 
        return result;
      }
    }

这样,用Transaction将执行代码块包起来,如果出现异常,在catch中 进行Rollback(回滚事务),就可以保证了数据的一致性。如果是高并发场景,可能还会需要用到锁,这里暂时不做延伸讨论。

如果是返回集合,也很容易处理:

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public async Task<List<实体>> GetClubsByUserId(int regattaId, int userId)
    {
      using (var conn = GetMySqlConnection(regattaId))
      {
        if (conn.State == ConnectionState.Closed)
        {
          await conn.OpenAsync();
        }
 
        const string sql =
          @"select b.club_id as id,c.name,c.image as ImageData,c.year,c.address,c.creator,c.description,b.contact ,b.phone,b.isvalid from 表1 a left join 表2 b on
           a.clubinfo_id=b.club_id left join 表3 c on
           b.clubbase_id=c.club_id where a.authorize_userid=@user_Id";
        List<实体> clubDetailList =
          (await conn.QueryAsync<实体>(sql, new { user_Id = userId }, commandType: CommandType.Text))
          .ToList();
 
        return clubDetailList;
      }
    }

关于Dapper的示例 本文就讲到这儿,大家可以上官网浏览了解更多:

https://dapper-tutorial.net/

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:http://www.cnblogs.com/zhangxiaoyong/p/10765693.html