FreeSql/Docs/update.md

更新数据

方法	返回值	参数	描述
SetSource	<this>	T1 | IEnumerable	更新数据，设置更新的实体
IgnoreColumns	<this>	Lambda	忽略的列
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;
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
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

列优先级

全部列 < 指定列(Set/SetRaw) < 忽略列(IgnoreColumns)

测试代码

[Table(Name = "tb_topic")]
class Topic {
	[Column(IsIdentity = true, IsPrimary = true)]
	public int Id { get; set; }
	public int Clicks { get; set; }
	public TestTypeInfo Type { get; set; }
	public string Title { get; set; }
	public DateTime CreateTime { get; set; }
}

IFreeSql fsql = new FreeSql.FreeSqlBuilder()
    .UseConnectionString(FreeSql.DataType.MySql, "Data Source=127.0.0.1;Port=3306;User ID=root;Password=root;Initial Catalog=cccddd;Charset=utf8;SslMode=none;Max pool size=10")
    .Build();
IUpdate<Topic> update => fsql.Update<Topic>();

动态条件

Update<Topic>(object dywhere)

dywhere 支持

• 主键值
• new[] { 主键值1, 主键值2 }
• Topic对象
• new[] { Topic对象1, Topic对象2 }
• new { id = 1 }

更新指定列

var t1 = fsql.Update<Topic>(1).Set(a => a.CreateTime, DateTime.Now).ToSql();
//UPDATE `tb_topic` SET `CreateTime` = '2018-12-08 00:04:59' WHERE (`Id` = 1)

更新指定列，累加

var t2 = fsql.Update<Topic>(1).Set(a => a.Clicks + 1).ToSql();
//UPDATE `tb_topic` SET `Clicks` = ifnull(`Clicks`,0) + 1 WHERE (`Id` = 1)

保存实体

var item = new Topic { Id = 1, Title = "newtitle" };
var t3 = update.SetSource(item).ToSql();
//UPDATE `tb_topic` SET `Clicks` = ?p_0, `Title` = ?p_1, `CreateTime` = ?p_2 WHERE (`Id` = 1)

保存实体，忽略一些列

var t4 = update.SetSource(item).IgnoreColumns(a => a.Clicks).ToSql();
//UPDATE `tb_topic` SET `Title` = ?p_0, `CreateTime` = ?p_1 WHERE (`Id` = 1)
var t5 = update.SetSource(item).IgnoreColumns(a => new { a.Clicks, a.CreateTime }).ToSql();
//UPDATE `tb_topic` SET `Title` = ?p_0 WHERE (`Id` = 1)

批量保存

var items = new List<Topic>();
for (var a = 0; a < 10; a++) items.Add(new Topic { Id = a + 1, Title = $"newtitle{a}", Clicks = a * 100 });

var t6 = update.SetSource(items).ToSql();
//UPDATE `tb_topic` SET `Clicks` = CASE `Id` WHEN 1 THEN ?p_0 WHEN 2 THEN ?p_1 WHEN 3 THEN ?p_2 WHEN 4 THEN ?p_3 WHEN 5 THEN ?p_4 WHEN 6 THEN ?p_5 WHEN 7 THEN ?p_6 WHEN 8 THEN ?p_7 WHEN 9 THEN ?p_8 WHEN 10 THEN ?p_9 END, `Title` = CASE `Id` WHEN 1 THEN ?p_10 WHEN 2 THEN ?p_11 WHEN 3 THEN ?p_12 WHEN 4 THEN ?p_13 WHEN 5 THEN ?p_14 WHEN 6 THEN ?p_15 WHEN 7 THEN ?p_16 WHEN 8 THEN ?p_17 WHEN 9 THEN ?p_18 WHEN 10 THEN ?p_19 END, `CreateTime` = CASE `Id` WHEN 1 THEN ?p_20 WHEN 2 THEN ?p_21 WHEN 3 THEN ?p_22 WHEN 4 THEN ?p_23 WHEN 5 THEN ?p_24 WHEN 6 THEN ?p_25 WHEN 7 THEN ?p_26 WHEN 8 THEN ?p_27 WHEN 9 THEN ?p_28 WHEN 10 THEN ?p_29 END WHERE (`Id` IN (1,2,3,4,5,6,7,8,9,10))

批量保存的场景，先查询20条记录，根据本地很复杂的规则把集合的值改完后

传统做法是循环20次保存，用 case when 只要一次就行

批量保存，忽略一些列

var t7 = update.SetSource(items).IgnoreColumns(a => new { a.Clicks, a.CreateTime }).ToSql();
//UPDATE `tb_topic` SET `Title` = CASE `Id` WHEN 1 THEN ?p_0 WHEN 2 THEN ?p_1 WHEN 3 THEN ?p_2 WHEN 4 THEN ?p_3 WHEN 5 THEN ?p_4 WHEN 6 THEN ?p_5 WHEN 7 THEN ?p_6 WHEN 8 THEN ?p_7 WHEN 9 THEN ?p_8 WHEN 10 THEN ?p_9 END WHERE (`Id` IN (1,2,3,4,5,6,7,8,9,10))

批量更新指定列

var t8 = update.SetSource(items).Set(a => a.CreateTime, DateTime.Now).ToSql();
//UPDATE `tb_topic` SET `CreateTime` = ?p_0 WHERE (`Id` IN (1,2,3,4,5,6,7,8,9,10))

指定列更新后，批量保存将失效

更新条件

除了顶上介绍的 dywhere 构造参数外，还支持 Where lambda/sql 方法

var t9 = update.Set(a => a.Title, "新标题").Where(a => a.Id == 1).ToSql();
//UPDATE `tb_topic` SET `Title` = '新标题' WHERE (Id = 1)

自定义SQL

var t10 = update.SetRaw("Title = {0}", "新标题").Where("Id = {0}", 1).ToSql();
//UPDATE `tb_topic` SET Title = '新标题' WHERE (Id = 1)
//sql语法条件，参数使用 {0}，与 string.Format 保持一致，无须加单引号，错误的用法：'{0}'

执行命令

方法	返回值	参数	描述
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