FreeSql （十二）更新数据时指定列

时间：2023-03-08 22:46:57
FreeSql （十二）更新数据时指定列 
var connstr = "Data Source=127.0.0.1;Port=3306;User ID=root;Password=root;" +

    "Initial Catalog=cccddd;Charset=utf8;SslMode=none;Max pool size=10";

static IFreeSql fsql = new FreeSql.FreeSqlBuilder()

    .UseConnectionString(FreeSql.DataType.MySql, connstr)

    .UseAutoSyncStructure(true) //自动同步实体结构到数据库

    .Build(); //请务必定义成 Singleton 单例模式

[Table(Name = "tb_topic")]

class Topic {

    [Column(IsIdentity = true, IsPrimary = true)]

    public int Id { get; set; }

    public int Clicks { get; set; }

    public string Title { get; set; }

    public DateTime CreateTime { get; set; }

}

更新指定列

fsql.Update<Topic>(1)

  .Set(a => a.CreateTime, DateTime.Now)

  .ExecuteAffrows();

//UPDATE `tb_topic` SET `CreateTime` = '2018-12-08 00:04:59'

//WHERE (`Id` = 1)

支持 Set() 多次，相当于拼接

更新指定列，累加

fsql.Update<Topic>(1)

  .Set(a => a.Clicks + 1)

  .Set(a => a.Time == DateTime.Now)

  .ExecuteAffrows();

//UPDATE `tb_topic` SET `Clicks` = ifnull(`Clicks`,0) + 1, `Time` = now()

//WHERE (`Id` = 1)

更新指定列，一次指定

fsql.Update<Topic>(1).Set(a => new Topic

  {

    Clicks = a.Clicks + 1,

    Time = DateTime.Now

  })

  .ExecuteAffrows();

//UPDATE `tb_topic` SET `Clicks` = `Clicks` + 1, `Time` = now()

//WHERE (`Id` = 1)

根据 Dto 更新

fsql.Update<T>()

  .SetDto(new { title = "xxx", clicks = 2 })

  .Where(a => a.Id == 1)

  .ExecuteAffrows();

//UPDATE `tb_topic` SET `Title` = ?p_0, `Clicks` = ?p_1

//WHERE (Id = 1)

fsql.Update<T>()

  .SetDto(new Dictionary<string, object> { ["title"] = "xxx", ["clicks"] = 2 })

  .Where(a => a.Id == 1)

  .ExecuteAffrows();

//效果同上

自定义SQL

fsql.Update<Topic>()

  .SetRaw("Title = @title", new { title = "新标题" })

  .Where("Id = @id", 1)

  .ExecuteAffrows();

//UPDATE `tb_topic` SET Title = @title WHERE (Id = @id)

API

方法 返回值 参数 描述
SetSource <this> T1 | IEnumerable 更新数据，设置更新的实体
Set <this> Lambda, value 设置列的新值，Set(a => a.Name, "newvalue")
Set <this> Lambda 设置列的的新值为基础上增加，Set(a => a.Clicks + 1)，相当于 clicks=clicks+1
SetDto <this> object 根据 dto 更新的方法
SetRaw <this> string, parms 设置值，自定义SQL语法，SetRaw("title = ?title", new { title = "newtitle" })
Where <this> Lambda 表达式条件，仅支持实体基础成员（不包含导航对象）
Where <this> string, parms 原生sql语法条件，Where("id = ?id", new { id = 1 })
Where <this> T1 | IEnumerable 传入实体或集合，将其主键作为条件
WhereExists <this> ISelect 子查询是否存在
WithTransaction <this> DbTransaction 设置事务对象
ToSql string 返回即将执行的SQL语句
ExecuteAffrows long 执行SQL语句，返回影响的行数
ExecuteUpdated List<T1> 执行SQL语句，返回更新后的记录

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