InsertOrUpdate下使用UpdateSet的行为让人困惑

[LeaFrock]

问题描述及重现代码：

假设有TestEntity表，实体定义如下：

    public class TestEntity
    {
        [Column(IsPrimary = true, IsIdentity = true)]
        public int Id { get; set; }

        public int Key { get; set; }

        public int Year { get; set; }

        public int Count { get; set; }
    }

现需要实现逻辑：创建一个实例，如果表中没有则插入新行；否则将表中命中的行Count列加1。

很容易写出以下代码：

        var statEntity = new TestEntity()
        {
            Key = 1,
            Year = 2026
        };
        var sql = freeSql.InsertOrUpdate<TestEntity>()
          .SetSource(statEntity, p => new { p.Key })
          .UpdateSet((a, b) => a.Count == a.Count + 1)
          .ToSql();

但实际生成的SQL是：

MERGE INTO [TestEntity] t1 
USING (SELECT 0 as [Id], 1 as [Key], 2026 as [Year], 0 as [Count] ) t2 ON (t1.[Key] = t2.[Key]) 
WHEN MATCHED THEN 
  update set [Year] = t2.[Year], [Count] = (t1.[Count] + 1)  -- Year被更新为2026！
WHEN NOT MATCHED THEN 
  insert ([Key], [Year], [Count]) 
  values (t2.[Key], t2.[Year], t2.[Count]);

调整代码v1：

        var sql = freeSql.InsertOrUpdate<TestEntity>()
          .SetSource(statEntity, p => new { p.Key })
          .UpdateSet((a, b) => a.Count == a.Count + 1)
          .UpdateColumns(a => a.Count)
          .ToSql();

SQL符合预期：

MERGE INTO [TestEntity] t1 
USING (SELECT 0 as [Id], 1 as [Key], 2026 as [Year], 0 as [Count] ) t2 ON (t1.[Key] = t2.[Key]) 
WHEN MATCHED THEN 
  update set [Count] = (t1.[Count] + 1) 
WHEN NOT MATCHED THEN 
  insert ([Key], [Year], [Count]) 
  values (t2.[Key], t2.[Year], t2.[Count]);

调整代码v2：

        var sql = freeSql.InsertOrUpdate<TestEntity>()
          .SetSource(statEntity, p => new { p.Key })
          .UpdateSet((a, b) => a.Count == a.Count + 1)
          .UpdateColumns(a => a.Year) // 故意为之
          .ToSql();

SQL：

MERGE INTO [TestEntity] t1 
USING (SELECT 0 as [Id], 1 as [Key], 2026 as [Year], 0 as [Count] ) t2 ON (t1.[Key] = t2.[Key]) 
WHEN MATCHED THEN 
  update set [Year] = t2.[Year], [Count] = (t1.[Count] + 1)  -- UodateColumn约束失效
WHEN NOT MATCHED THEN 
  insert ([Key], [Year], [Count]) 
  values (t2.[Key], t2.[Year], t2.[Count]);

调整UpdateColumns和UpdateSet顺序，对结果没有影响。

以上行为实在让人困惑，尤其文档中没有明确UpdateColumn和UpdateSet的组合关系，极易让开发者误会导致数据被错误覆盖。

数据库版本

SqlServer 2016

安装的Nuget包

3.5.309

.net framework/. net core？ 及具体版本

.NET 10

[2881099]

SetSource + UpdateColumns 这个组件的规则，延用了 IUpdate 文档的说明。

UpdateSet 对应 IUpdate.Set，因此这个是独立的，优先级最大。

IUpdate 文档

https://github.com/dotnetcore/FreeSql/wiki/%e4%bf%ae%e6%94%b9#6setsetsourcesetdto-%E5%8C%BA%E5%88%AB