[英]Entity Framework Code First Mapping
我有两个类,Group类与User类有多对多关系(表示用户所属的组),然后该组与用户类(表示组的所有者)之间也存在一对多的关系)。
我该如何映射?
public class User
{
public int Id { get; set; }
public string Avatar { get; set; }
public string Name { get; set; }
public string Message { get; set; }
public virtual ICollection<Group> OwnedGroups { get; set; }
public virtual ICollection<Group> Groups { get; set; }
}
public class Group
{
public int Id { get; set; }
public DateTime CreateDate { get; set; }
public DateTime ModifyDate { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public bool System { get; set; }
public int ViewPolicy { get; set; }
public int JoinPolicy { get; set; }
public string Avatar { get; set; }
public int Order { get; set; }
public int GroupType { get; set; }
public virtual User Owner { get; set; }
public virtual ICollection<User> Members { get; set; }
}
事先提前!
我会使用流畅的API:
public class Context : DbContext
{
public DbSet<User> Users { get; set; }
public DbSet<Group> Groups { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<User>()
.HasMany(u => u.Groups)
.WithMany(g => g.Members);
modelBuilder.Entity<User>()
.HasMany(u => u.OwnedGroups)
.WithRequired(g => g.Owner)
.WillCascadeOnDelete(false);
}
}
它也应该可以使用数据注释:
public class User
{
...
[InverseProperty("Owner")]
public virtual ICollection<Group> OwnedGroups { get; set; }
[InverseProperty("Members")]
public virtual ICollection<Group> Groups { get; set; }
}
public class Group
{
...
[InverseProperty("OwnedGroups")]
public virtual User Owner { get; set; }
[InverseProperty("Groups")]
public virtual ICollection<User> Members { get; set; }
}
在关系的两个方面都不需要InverseProperty
,但它的定义更清晰。
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