我有两个表项目和任务.任务是项目的弱实体,因此任务的复合主键是(ProjectId& TaskID).我尝试使用以下代码,但它给出了一个错误
Cannot define PRIMARY KEY constraint on nullable column in table ‘Tasks’.
我正在使用代码优先的方法来创建表,我确保列不是null,但它仍然无法正常工作.请帮忙！
public class Task
{
[ForeignKey("ProjectId")]
public Project Project { get; set; }
[required]
public int ProjectId { get; set; }
//[Key,Column(Order = 1)]
[required]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public virtual int TaskID { get; set; }
...
}
//using FluentAPI
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Task>().Hasrequired(p => p.Project);
modelBuilder.Entity<Task>().HasKey(p => new { p.ProjectId,p.TaskID });
modelBuilder.Entity<Project>()
.Hasrequired(e=> e.Employee)
.WithMany()
.WillCascadeOnDelete(false);
}
解决方法
遇到这个寻找别的东西,有点晚了,但这对我来说很好地映射到一个复合键
[Key,Column(Order=1) ]
public int KeyId { get; set; }
[Key,Column(Order = 2)]
public int Key1Id { get; set; }
[Key,Column(Order = 3)]
public int Key2Id { get; set; }
[Key,Column(Order = 4)]
public int Key3Id { get; set; }
希望这有助于某人.
