最好的解决方案是使用GeneratedValue(strategy =…)注释，即。

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column ...
private int OperationID;

它说，这个列是由数据库使用IDENTITY策略生成的，你不需要关心-数据库会做的。

在我的例子中，我已经在modelBuilder的上下文中设置了另一个属性作为键。

modelBuilder.Entity<MyTable>().HasKey(t => t.OtherProp);

我必须设置正确的id

 modelBuilder.Entity<MyTable>().HasKey(t => t.Id);

EF Core 3.x

引用Leniel Maccaferri，我有一个带有自动递增属性的表，称为ID(原始主键)和另一个属性称为Other_ID(新的主键)。最初ID是主键，但后来Other_ID需要成为新的主键。由于ID正在应用程序的其他部分使用，我不能只是从表中删除它。Leniel Maccaferri解决方案只适用于我之后，我添加了以下片段:

        entity.HasKey(x => x.Other_ID);
        entity.Property(x => x.ID).ValueGeneratedOnAdd();

完整代码片段如下(ApplicationDbContext.cs):

  protected override void OnModelCreating(ModelBuilder builder)
  {
        builder.ApplyConfigurationsFromAssembly(Assembly.GetExecutingAssembly());
        base.OnModelCreating(builder);
        builder.Entity<tablename>(entity =>
        {
            entity.HasKey(x => x.Other_ID);
            entity.Property(x => x.ID).ValueGeneratedOnAdd();
            entity.HasAlternateKey(x => new { x.Other_ID, x.ID });                
        });
        
    }

This occurs when you have a (Primary key) column that is not set to Is Identity to true in SQL and you don't pass explicit value thereof during insert. It will take the first row, then you wont be able to insert the second row, the error will pop up. This can be corrected by adding this line of code [DatabaseGenerated(DatabaseGeneratedOption.Identity)] in your PrimaryKey column and make sure its set to a data type int. If the column is the primary key and is set to IsIDentity to true in SQL there is no need for this line of code [DatabaseGenerated(DatabaseGeneratedOption.Identity)] this also occurs when u have a column that is not the primary key, in SQL that is set to Is Identity to true, and in your EF you did not add this line of code [DatabaseGenerated(DatabaseGeneratedOption.Identity)]

在您的查询中有前面提到的OperationId，它不应该在那里，因为它是自动递增的

Insert table(OperationID,OpDescription,FilterID)
values (20,'Hierachy Update',1)

所以你的问题是

Insert table(OpDescription,FilterID)
values ('Hierachy Update',1)

即使一切正确，如果Identity列的数据类型不是int或long，也会出现此错误。我有单位列为十进制，虽然我只保存int值(我的坏)。更改数据库和底层模型中的数据类型为我解决了这个问题。