[英]Entity Framework many to many relationship add/update
我有兩個實體,當我更新或添加一個實體時就可以了
db.Entry(user1).State = EntityState.Modified;
foreach (var userAudio in user1.Audios)
{
db.Audios.AddOrUpdate(userAudio);
}
db.Users.AddOrUpdate(user1);
db.SaveChanges();
但是,如果我嘗試添加/更新幾個實體:
db.Entry(user1).State = EntityState.Modified;
foreach (var userAudio in user1.Audios)
{
db.Audios.AddOrUpdate(userAudio);
}
db.Users.AddOrUpdate(user1);
db.Entry(user2).State = EntityState.Modified;
foreach (var userAudio in user2.Audios)
{
db.Audios.AddOrUpdate(userAudio);
}
db.Users.AddOrUpdate(user2);
db.SaveChanges();
它拋出異常:
附加類型為'EfTest.Entities.Audio'的實體失敗,因為相同類型的另一個實體已經具有相同的主鍵值...
可能是因為我在user1和user2中有相同的音頻,而EF無法插入它們...任何人都對如何解決這個問題有想法? 謝謝!
實體
namespace EfTest.Entities
{
public class User
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int Id { get; set; }
public string Name { get; set; }
public int Age { get; set; }
public List<Audio> Audios { get; set; }
}
public class Audio
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int Id { get; set; }
public string Artist { get; set; }
public string Title { get; set; }
public List<User> Users { get; set; }
}
}
不幸的是,我只看到解決此問題的一種方法。 它是獨立添加實體,然后添加關系:
var userAudios = new List<Audio>();
// Key userId
// Value list of audiosIds
var userAudiosRelations = new List<Relation>();
foreach (var user in users)
{
foreach (var audio in user.Audios)
{
if (!userAudios.Any(x => x.Id == audio.Id))
{
userAudios.Add(audio);
}
userAudiosRelations.Add(new Relation
{
User_Id = user.Id,
Audio_Id = audio.Id
});
}
user.Audios = null;
db.Users.AddOrUpdate(user);
}
foreach (var audio in userAudios)
{
db.Audios.AddOrUpdate(audio);
}
db.SaveChanges();
var existingRelations = db.Database.SqlQuery<Relation>("SELECT * FROM dbo.UserAudios").ToList();
var relationsToAdd =
userAudiosRelations.Where(
x => existingRelations.All(y => x.User_Id != y.User_Id || x.Audio_Id != y.Audio_Id)).ToList();
foreach (var relation in relationsToAdd)
{
db.Database.ExecuteSqlCommand("INSERT INTO dbo.UserAudios (User_Id, Audio_Id) VALUES (@p0, @p1)",
relation.User_Id, relation.Audio_Id);
}
關系模型:
public class Relation
{
public int User_Id { get; set; }
public int Audio_Id { get; set; }
}
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