I have been having a problem with updating my migration. I am able to generate the migration just fine. I learned these techniques for seeding the database from the book C# 10 and .NET 6 by Mark J. Price. I have applied the techniques that I learned, although incorrectly as it may seem, while following along with IAmTimCorey's Suggestion Site App Playlist on YouTube. He uses MongoDB, but I have chosen to use SQL Server with EF Core. I have a few one-to-one relationships but this one many-many relationship that I highlighted below is throwing the error.
SuggestionModel.cs
[Key]
public long SuggestionId { get; set; }
...
public ICollection<UserModel> UserVotes { get; set; } = new HashSet<UserModel>();
...
UserModel.cs
[Key]
public long UserId { get; set; }
...
public ICollection<SuggestionModel> VotedOnSuggestions { get; set; } = new List<SuggestionModel>();
...
DbConnection.cs (DbContext class)
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
...
modelBuilder.Entity<UserModel>().HasData(user1, user2, user3, user4);
modelBuilder.Entity<SuggestionModel>().HasData(suggestion1, suggestion2, suggestion3, suggestion4, suggestion5);
modelBuilder.Entity<SuggestionModel>().HasMany(s => s.UserVotes).WithMany(u => u.VotedOnSuggestions)
.UsingEntity(e => e.HasData(
new { VotedOnSuggestionsSuggestionId = 4L, UserVotesUserId = 1L },
new { VotedOnSuggestionsSuggestionId = 4L, UserVotesUserId = 2L },
new { VotedOnSuggestionsSuggestionId = 4L, UserVotesUserId = 3L },
new { VotedOnSuggestionsSuggestionId = 5L, UserVotesUserId = 1L },
new { VotedOnSuggestionsSuggestionId = 5L, UserVotesUserId = 2L },
new { VotedOnSuggestionsSuggestionId = 5L, UserVotesUserId = 3L },
new { VotedOnSuggestionsSuggestionId = 5L, UserVotesUserId = 4L }
));
}
The exact error
Microsoft.Data.SqlClient.SqlException (0x80131904): Introducing FOREIGN KEY constraint
'FK_SuggestionModelUserModel_Users_UserVotesUserId' on table 'SuggestionModelUserModel'
may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO
ACTION, or modify other FOREIGN KEY constraints.
SQL Command that caused the error
Failed executing DbCommand (10ms) [Parameters=[], CommandType='Text',
CommandTimeout='30']
CREATE TABLE [SuggestionModelUserModel] (
[UserVotesUserId] bigint NOT NULL,
[VotedOnSuggestionsSuggestionId] bigint NOT NULL, CONSTRAINT
[PK_SuggestionModelUserModel] PRIMARY KEY ([UserVotesUserId],
[VotedOnSuggestionsSuggestionId]),
CONSTRAINT [FK_SuggestionModelUserModel_Suggestions_VotedOnSuggestionsSuggestionId]
FOREIGN KEY ([VotedOnSuggestionsSuggestionId]) REFERENCES [Suggestions]
([SuggestionId]) ON DELETE CASCADE,
CONSTRAINT [FK_SuggestionModelUserModel_Users_UserVotesUserId] FOREIGN KEY
([UserVotesUserId]) REFERENCES [Users] ([UserId]) ON DELETE CASCADE
);
EDIT: The only thing that I changed in my code that was different from what I learned was that I initialize both UserVotes and VotedOnSuggestions as different collections. UserVotes has to be a HashSet and VotedOnSuggestions must be a List
