蓝灯软件数据股份有限公司项目，代码开源。

SqlSugar是一款轻量级的MSSQL ORM ，除了具有媲美ADO的性能外还具有和EF相似简单易用的语法。

学习列表

0、功能更新

1、SqlSugar基础应用

2、使用SqlSugar处理大数据

3、使用SqlSugar实现Join 待更新

4、使用SqlSugar实现分页+分组+多列排序待更新

5、节点故障如何进行主从调换

一、介简

优点：

1、优越的性能，查询使用 reflection.emit 创建IL语言+委托绑定然后对该对象进行 cache ,datareader直接赋值给cache对象,高性能拉姆达解析，总体性能媲美 ADO.NET ，查询速度稍慢于datareader但稍快于datatable

2、大量语法糖，拉姆达表达示筛选，新颖的多表查询，方便的分页等

3、支持NOLOCK查询，提高性能

4、支持事务

5、内置实体类生成函数，无需使用第三方代码生成器

6、简单好用、例子齐全有问必答。

缺点：

目前只支持MSSQL，以后会全面发展

组成：

sqlSugar是由sqlSugarClientr提供统一调用模式，sqlSugarClientr是由5个部分组成

1、自身函数

2、实体生成

3、单表查询

4、多表查询

5、基类函数

如图：

二、使用教程

查询

1、单表或者单视图查询：

通过调用 db.Queryable() 的相关扩展函数轻松搞定单表查询

using (SqlSugarClient db = new SqlSugarClient(connStr))//开启数据库连接
        {
 
                  
                   //查询所有
                    var student = db.Queryable<Student>().ToList();
 
                    //查询单条
                    var single = db.Queryable<Student>().Single(c => c.id == 1);
 
                    //取10-20条
                    var page1 = db.Queryable<Student>().Where(c => c.id > 10).OrderBy("id").Skip(10).Take(20).ToList();
                    //上一句的简化写法，同样取10-20条
                    var page2 = db.Queryable<Student>().Where(c => c.id > 10).OrderBy("id").ToPageList(2, 10);
 
                    //查询条数
                    var count = db.Queryable<Student>().Where(c => c.id > 10).Count();
 
                    //从第2条开始以后取所有
                    var skip = db.Queryable<Student>().Where(c => c.id > 10).OrderBy("id").Skip(2).ToList();
 
                    //取前2条
                    var take = db.Queryable<Student>().Where(c => c.id > 10).OrderBy("id").Take(2).ToList();
 
                    // Not like 
                    var notLike = db.Queryable<Student>().Where(c => !c.name.Contains("a".ToString())).ToList();
 
                    // 可以在拉姆达使用 ToString和 Convert,比EF出色的地方
                    var convert1 = db.Queryable<Student>().Where(c => c.name == "a".ToString()).ToList();
                    var convert2 = db.Queryable<Student>().Where(c => c.id == Convert.ToInt32("1")).ToList();// 
                    var convert3 = db.Queryable<Student>().Where(c => DateTime.Now > Convert.ToDateTime("2015-1-1")).ToList();
                    var convert4 = db.Queryable<Student>().Where(c => DateTime.Now > DateTime.Now).ToList();
 
                    //支持字符串Where 让你解决，更复杂的查询
                    var student12 = db.Queryable<Student>().Where(c => 1 == 1).Where("id>@id",new{id=1}).ToList();
 
 ｝

//存在记录反回true，则否返回false
 bool isAny100 = db.Queryable<Student>().Any(c => c.id == 100);
 bool isAny1 = db.Queryable<Student>().Any(c => c.id == 1);

2、单表高级查询

根据条件查询并分页　

/// <summary>
      /// 根据条件查询并且分页
      /// </summary>
      /// <param name="name"></param>
      /// <param name="sex"></param>
      /// <returns></returns>
      public static List<Student> GetStudent(string name, string sex, int pageIndex, int pageSize, string orderFileds,out int pageCount)
      {
          using (SqlSugarClient db = SugarDao.GetInstance())
          {
              var qable = db.Queryable<Student>();
              if (!string.IsNullOrEmpty(name))
              {
                  qable = qable.Where(it => it.name.Contains(name));
              }
              if (!string.IsNullOrEmpty(sex))
              {
                  qable = qable.Where(it => it.sex == sex);
              }
              if (!string.IsNullOrEmpty(orderFileds))//无需担心注入
              {
                  qable = qable.OrderBy(orderFileds);
              }
              pageCount = qable.Count();
              return qable.ToPageList(pageIndex, pageSize);
          }
      }

新容器转换

public List<classNew> GetSelectList(int id)
{
    using (SugarDao db = new SugarDao())
    {
        return db.Queryable<Student>().Where(c=>c.id<10).Select(c => new classNew { newid = c.id, newname = c.name,xx_name=c.name }).ToList();//不支持匿名类转换,也不建议使用
    }
}

分组查询

public List<SexTotal> GetSexTotal()
       {
           using (SugarDao db = new SugarDao())
           {
               return db.Queryable<Student>().Where(c => c.id < 20).GroupBy("sex").Select<Student, SexTotal>("Sex,Count=count(*)").ToList();
           }
       }

1	`SELECT` `Sex,Count=count(*)` `FROM` `Student` `WHERE` `1=1` `AND` `(id < 20)` `GROUP` `BY` `Sex` `--生成结果`

3、多表查询：

说到多表查询在众多ORM中无论是性能还是功能上都不满意，或者说还不如用SQL，下面是我的创意，放弃了强类型写法，让代码更接近SQL语句编写，让SQL完全可控，也解决了OMR多表的性能问题。

还有ORDERBY、GROUPBY和APPLY等，例子中就不介绍了。

拿EF来比较一下：

EF查询:

var reval = (from s in db.Student
                               join sc in db.School on s.sch_id equals sc.id
                               join sb in db.Subject on s.id equals sb.sid
                               into ssb
                               from sb2 in ssb.DefaultIfEmpty()
                               select new {
                               s.id,
                               s.name,
                               s.sch_id,
                               s.sex
                               }).Where(c=>c.id>1).Where(c=>c.id>2).OrderBy(c=>c.id).ThenByDescending(c=>c.name).Skip(10).Take(10).ToList();

SqlSugar查询:

db.Sqlable().Form<Student>("s")
                  .Join<School> ("sc", "sc.id", "s.sch_id", JoinType.INNER)
                  .Join<subject>("sb", "sb.sid", "s.id", JoinType.LEFT).Where("s.id>@id1").Where("s.id>@id2")
                  .SelectToPageList<Models.Student>("s.*", "s.id asc,s.name desc", 2, 10, new { id1=1,id2=2 });

更多的SqlSugar查询：

//表名是字符串写法
List<School> dataList = db.Sqlable()
   .Form("school", "s")
   .Join("student", "st", "st.id", "s.id", JoinType.INNER)
   .Join("student", "st2", "st2.id", "st.id", JoinType.LEFT).Where("s.id>100 and s.id<@id").SelectToList<School>("st.*", new { id = 1 });
 
//多表分页
List<School> dataPageList = db.Sqlable()
    .Form<school>("s")
    .Join<student>("st", "st.id", "s.id", JoinType.INNER)
    .Join<student>("st2", "st2.id", "st.id", JoinType.LEFT).Where("s.id>100 and s.id<100").SelectToPageList<School>("st.*", "s.id", 1, 10);

子查询加动态拼接

public List<Student> GetStudent(int id, string name)
       {
           int pageCount = 0;
           using (var db = SugarDao.GetInstance())
           {
               //Form("Student","s")语法优化成 Form<Student>("s")
               var sable = db.Sqlable().Form<Student>("s").Join<School>("l", "s.sch_id", "l.id", JoinType.INNER);
               if (!string.IsNullOrEmpty(name))
               {
                   sable = sable.Where("s.name=@name");
               }
               if (!string.IsNullOrEmpty(name))
               {
                   sable = sable.Where("s.id=@id or s.id=100");
               }
               if (id > 0) {
                   sable = sable.Where("l.id in (select top 10 id from school)");//where加子查询
               }
               //参数
               var pars = new { id = id, name = name };
               pageCount = sable.Count(pars);
               return sable.SelectToList<Student>("s.*", pars);
           }
       }

4、使用SQL或者存储过程查询：

为了兼容上面满足不了的情况所以也写了这么个函数以便应急之需

var School = db.SqlQuery<School>("select * from School");
 
                    //获取id
                    var id = db.SqlQuery<int>("select top 1 id from School").Single();
 
                    //存储过程
                    //var spResult = db.SqlQuery<school>("exec sp_school @p1,@p2", new { p1=1,p2=2 });
                      
                    //无返回值
                    db.ExecuteCommand(sql);

添加

using (SqlSugarClient db = new SqlSugarClient(connStr))//开启数据库连接
{
 
            School s = new School()
            {
                name = "蓝翔"
            };
 
            //插入单条
            var id2 = Convert.ToInt32(db.Insert(s));
 
            //插入多条
            List<School> sList = new List<School>();
            sList.Add(s);
            var ids = db.InsertRange(sList);
 }

修改

//指定列更新
db.Update<School>(new { name = "蓝翔2" }, it => it.id == id);
//整个实体更新,注意主键必需为实体类的第一个属性
db.Update<School>(new School { id = id, name = "蓝翔2" }, it => it.id == id);

删除

db.Delete<School>(id);//注意主键必需为实体类的第一个属性
db.Delete<School>(it => it.id > 100);
db.Delete<School>(new string[] { "100", "101", "102" });
   
 db.FalseDelete<school>("is_del", 100);//假删除
 //等同于 update school set is_del=0 where id in(100)<br>
 db.FalseDelete<school>("is_del", it=>it.id==100);

实体生成

using (SqlSugarClient db = new SqlSugarClient(connStr))//开启数据库连接
 {
 
                  //根据当前数据库生成所有表的实体类文件 （参数：SqlSugarClient ，文件目录，命名空间）
                    db.ClassGenerating.CreateClassFiles(db,Server.MapPath("~/Models"),"Models");
                    //根据表名生成实体类文件
                    db.ClassGenerating.CreateClassFilesByTableNames(db, Server.MapPath("~/Models"), "Models" , "student","school");
 
                    //根据表名生成class字符串
                    var str = db.ClassGenerating.TableNameToClass(db, "Student");
 
                    //根据SQL语句生成class字符串
                    var str2 = db.ClassGenerating.SqlToClass(db, "select top 1 * from Student", "student");
｝

事务

using (SqlSugarClient db = new SqlSugarClient(connStr))//开启数据库连接
{
   try{
       //开启事务，可以不使用事务,也可以使用多个事务
        db.BeginTran();
         
        //sq1
        //sql2
        //sql3 
 
    }catch (Exception ex){
       //回滚事务
       db.RollbackTran();
       throw ex;
    }
 
}//关闭数据库连接

无锁查询

　　当IsNoLock设为True时，查询生成的SQL语句表名的后面都会带有With(Nolock)

using (SqlSugarClient db = new SqlSugarClient(connStr))//开启数据库连接
{
          db.IsNoLock = true;
          //sql xxx with(nolock)
          db.IsNoLock = false;
          //sql xxx
          //sql xxx
          db.IsNoLock = true;
          //sql xxx with(nolock)
 
}//关闭数据库连接

支持多库切换的写法

定义一个sugarDao类来扩展SqlSugar

/// <summary>
  /// 扩展SqlSugarClient
  /// </summary>
  public class SugarDao
  {
      //禁止实例化
      private SugarDao() { 
 
      }
      public static SqlSugarClient GetInstance()
      {
          string connection = "Server=.;uid=sa;pwd=sasa;database=SqlSugarTest"; //这里可以动态根据cookies或session实现多库切换
          return new SqlSugarClient(connection);
      }
  }

使用无需传入connectionString

public School GetSingleSchool(int id)
  {
      using (SqlSugarClient db = SugarDao.GetInstance())
      {
          return db.Queryable<School>().Single(c => c.id == id);
      }
  }