我正在使用EF6 Code First。我有两节课:
public class Player
{
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
[Key]
public int Id { get; set; }
[Required, MinLength(2, ErrorMessage = "Player name must be at least 2 characters length")]
public string Name { get; set; }
[Required]
public int TeamClubId { get; set; }
[Required]
public int TeamNationalId { get; set; }
[Required, ForeignKey("TeamClubId")]
public virtual Team Club { get; set; }
[Required, ForeignKey("TeamNationalId")]
public virtual Team National { get; set; }
}
和:
public class Team
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[Required, MinLength(2, ErrorMessage = "Team name must be at least 2 characters length")]
public string Name { get; set; }
[Required]
public TeamType Type { get; set; }
public virtual ICollection<Player> Players { get; set; }
}
这是我两个班级的关系。一个球员属于两支球队:俱乐部和国家队。一支球队可以是俱乐部,也可以是国家队,并拥有一批球员。
在我的上下文文件中,我使用:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Player>()
.HasRequired<Team>(p => p.National)
.WithMany(t => t.Players)
.WillCascadeOnDelete(false);
base.OnModelCreating(modelBuilder);
}
运行迁移工具更新数据库时,出现以下错误:
在表“播放器”上引入外键约束“ FK_dbo.Players_dbo.Teams_TeamNationalId”可能会导致循环或多个级联路径。指定ON DELETE NO ACTION或ON UPDATE NO ACTION,或修改其他FOREIGN KEY约束。无法创建约束。请参阅先前的错误。
我该如何解决?
使用Fluent API:
//player - national team relations
modelBuilder.Entity<Player>()
.HasRequired<Team>(p => p.National)
.WithMany()
.WillCascadeOnDelete(false);
//player - club team relations
modelBuilder.Entity<Player>()
.HasRequired<Team>(p => p.Club)
.WithMany()
.WillCascadeOnDelete(false);
本文收集自互联网,转载请注明来源。
如有侵权,请联系[email protected] 删除。
我来说两句