I have a model class in my Blazor Server project as follows
public class TestModel
{
public Client Client { get; set; }
... other value types follow etc.
}
My Client class is defined as below:
public class Client
{
public string ClientID { get; set; }
public string ClientName { get; set; }
public ICollection<SetupModel> SetupModels { get; set; }
}
Client loads from a view and will never be updated by my application (users change its value using a dropdown). I am defining this as a one to many relation in OnModelCreating as each Client can have many TestModels.
modelBuilder.Entity<Client>().HasMany(x => x.SetupModels).WithOne(x=> x.Client);
The ClientID shadow property of TestModel need to be updated whenever the user changes the Client in a dropdown. I am using local storage to handle drafts so it is not possible to use traditional entity tracking, as I often need to parse json back into the relevant classes. My first attempt was to use Entry.CurrentValues.SetValues:
using var context = Factory.CreateDbContext();
var existing = await context.SetupForm.SingleOrDefaultAsync(x => x.ID == model.ID);
context.Entry(existing).CurrentValues.SetValues(model);
await context.SaveChangesAsync();
SetValues doesn't work for reference properties, however, so I am stuck unable to update the foreign key on my TestModel in this disconnected scenario. I have spent several hours on this today and think I am overlooking something simple. How should I handle this scenario?
Given the following set up where there are many Teams and there are many LeagueSessions. Each Team belongs to zero or more LeagueSessions but only ever one LeagueSession is active. LeagueSessions have many teams, and the teams will be repeated. Many-to-many relationship is established between Teams and LeagueSessions with a join table called TeamsSessions.
Team model looks like this:
public class Team
{
public string Id { get; set; }
public string Name { get; set; }
public League League { get; set; }
public string LeagueID { get; set; }
public bool Selected { get; set; }
public ICollection<Match> Matches { get; set; }
public virtual ICollection<TeamSession> TeamsSessions { get; set; }
}
Team model fluent api configuration:
`
public class TeamConfiguration
{
public TeamConfiguration(EntityTypeBuilder<Team> model)
{
// The data for this model will be generated inside ThePLeagueDataCore.DataBaseInitializer.DatabaseBaseInitializer.cs class
// When generating data for models in here, you have to provide it with an ID, and it became mildly problematic to consistently get
// a unique ID for all the teams. In ThePLeagueDataCore.DataBaseInitializer.DatabaseBaseInitializer.cs we can use dbContext to generate
// unique ids for us for each team.
model.HasOne(team => team.League)
.WithMany(league => league.Teams)
.HasForeignKey(team => team.LeagueID);
}
}
`
Each team belongs to a single League. League model looks like this:
`public class League
{
public string Id { get; set; }
public string Type { get; set; }
public string Name { get; set; }
public IEnumerable<Team> Teams { get; set; }
public bool Selected { get; set; }
public string SportTypeID { get; set; }
public SportType SportType { get; set; }
public IEnumerable<LeagueSessionSchedule> Sessions { get; set; }
}`
fluent API for the League:
`public LeagueConfiguration(EntityTypeBuilder<League> model)
{
model.HasOne(league => league.SportType)
.WithMany(sportType => sportType.Leagues)
.HasForeignKey(league => league.SportTypeID);
model.HasMany(league => league.Teams)
.WithOne(team => team.League)
.HasForeignKey(team => team.LeagueID);
model.HasData(leagues);
}`
SessionScheduleBase class looks like this:
public class SessionScheduleBase
{
public string LeagueID { get; set; }
public bool ByeWeeks { get; set; }
public long? NumberOfWeeks { get; set; }
public DateTime SessionStart { get; set; }
public DateTime SessionEnd { get; set; }
public ICollection<TeamSession> TeamsSessions { get; set; } = new Collection<TeamSession>();
public ICollection<GameDay> GamesDays { get; set; } = new Collection<GameDay>();
}
Note: LeagueSessionSchedule inherits from SessionScheduleBase
The TeamSession model looks like this:
`public class TeamSession
{
public string Id { get; set; }
public string TeamId { get; set; }
public Team Team { get; set; }
public string LeagueSessionScheduleId { get; set; }
public LeagueSessionSchedule LeagueSessionSchedule { get; set; }
}`
I then configure the relationship with the fluent API like this:
`public TeamSessionConfiguration(EntityTypeBuilder<TeamSession> model)
{
model.HasKey(ts => new { ts.TeamId, ts.LeagueSessionScheduleId });
model.HasOne(ts => ts.Team)
.WithMany(t => t.TeamsSessions)
.HasForeignKey(ts => ts.TeamId);
model.HasOne(ts => ts.LeagueSessionSchedule)
.WithMany(s => s.TeamsSessions)
.HasForeignKey(ts => ts.LeagueSessionScheduleId);
}`
The problem arises whenever I attempt to insert a new LeagueSessionSchedule. The way I am adding a new TeamSession object onto the new LeagueSessionSchedule is like this:
`foreach (TeamSessionViewModel teamSession in newSchedule.TeamsSessions)
{
Team team = await this._teamRepository.GetByIdAsync(teamSession.TeamId, ct);
if(team != null)
{
TeamSession newTeamSession = new TeamSession()
{
Team = team,
LeagueSessionSchedule = leagueSessionSchedule
};
leagueSessionSchedule.TeamsSessions.Add(newTeamSession);
}
}`
Saving the new LeagueSessionSchedule code:
public async Task<LeagueSessionSchedule> AddScheduleAsync(LeagueSessionSchedule newLeagueSessionSchedule, CancellationToken ct = default)
{
this._dbContext.LeagueSessions.Add(newLeagueSessionSchedule);
await this._dbContext.SaveChangesAsync(ct);
return newLeagueSessionSchedule;
}
Saving the new LeagueSessionSchedule object throws an error by Entity Framework Core that it cannot INSERT a duplicate primary key value into the dbo.Teams table. I have no idea why its attempting to add to dbo.Teams table and not into TeamsSessions table.
ERROR:
INSERT INTO [LeagueSessions] ([Id], [Active], [ByeWeeks], [LeagueID], [NumberOfWeeks], [SessionEnd], [SessionStart])
VALUES (#p0, #p1, #p2, #p3, #p4, #p5, #p6);
INSERT INTO [Teams] ([Id], [Discriminator], [LeagueID], [Name], [Selected])
VALUES (#p7, #p8, #p9, #p10, #p11),
(#p12, #p13, #p14, #p15, #p16),
(#p17, #p18, #p19, #p20, #p21),
(#p22, #p23, #p24, #p25, #p26),
(#p27, #p28, #p29, #p30, #p31),
(#p32, #p33, #p34, #p35, #p36),
(#p37, #p38, #p39, #p40, #p41),
(#p42, #p43, #p44, #p45, #p46);
System.Data.SqlClient.SqlException (0x80131904): Violation of PRIMARY KEY constraint 'PK_Teams'. Cannot insert duplicate key in object 'dbo.Teams'. The duplicate key value is (217e2e11-0603-4239-aab5-9e2f1d3ebc2c).
My goal is to create a new LeagueSessionSchedule object. Along with the creation of this object, I also have to create a new TeamSession entry to the join table (or not if join table is not necessary) to then be able to pick any given team and see what session it is currently a part of.
My entire PublishSchedule method is the following:
`
public async Task<bool> PublishSessionsSchedulesAsync(List<LeagueSessionScheduleViewModel> newLeagueSessionsSchedules, CancellationToken ct = default(CancellationToken))
{
List<LeagueSessionSchedule> leagueSessionOperations = new List<LeagueSessionSchedule>();
foreach (LeagueSessionScheduleViewModel newSchedule in newLeagueSessionsSchedules)
{
LeagueSessionSchedule leagueSessionSchedule = new LeagueSessionSchedule()
{
Active = newSchedule.Active,
LeagueID = newSchedule.LeagueID,
ByeWeeks = newSchedule.ByeWeeks,
NumberOfWeeks = newSchedule.NumberOfWeeks,
SessionStart = newSchedule.SessionStart,
SessionEnd = newSchedule.SessionEnd
};
// leagueSessionSchedule = await this._sessionScheduleRepository.AddScheduleAsync(leagueSessionSchedule, ct);
// create game day entry for all configured game days
foreach (GameDayViewModel gameDay in newSchedule.GamesDays)
{
GameDay newGameDay = new GameDay()
{
GamesDay = gameDay.GamesDay
};
// leagueSessionSchedule.GamesDays.Add(newGameDay);
// create game time entry for every game day
foreach (GameTimeViewModel gameTime in gameDay.GamesTimes)
{
GameTime newGameTime = new GameTime()
{
GamesTime = DateTimeOffset.FromUnixTimeSeconds(gameTime.GamesTime).DateTime.ToLocalTime(),
// GameDayId = newGameDay.Id
};
// newGameTime = await this._sessionScheduleRepository.AddGameTimeAsync(newGameTime, ct);
newGameDay.GamesTimes.Add(newGameTime);
}
leagueSessionSchedule.GamesDays.Add(newGameDay);
}
// update teams sessions
foreach (TeamSessionViewModel teamSession in newSchedule.TeamsSessions)
{
// retrieve the team with the corresponding id
Team team = await this._teamRepository.GetByIdAsync(teamSession.TeamId, ct);
if(team != null)
{
TeamSession newTeamSession = new TeamSession()
{
Team = team,
LeagueSessionSchedule = leagueSessionSchedule
};
leagueSessionSchedule.TeamsSessions.Add(newTeamSession);
}
}
// update matches for this session
foreach (MatchViewModel match in newSchedule.Matches)
{
Match newMatch = new Match()
{
DateTime = match.DateTime,
HomeTeamId = match.HomeTeam.Id,
AwayTeamId = match.AwayTeam.Id,
LeagueID = match.LeagueID
};
leagueSessionSchedule.Matches.Add(newMatch);
}
try
{
leagueSessionOperations.Add(await this._sessionScheduleRepository.AddScheduleAsync(leagueSessionSchedule, ct));
}
catch(Exception ex)
{
}
}
// ensure all leagueSessionOperations did not return any null values
return leagueSessionOperations.All(op => op != null);
}
`
This is not a many-to-many relationship.
It is two separate one-to-many relationships, which happen to refer to the same table on one end of the relationship.
While it is true that on the database level, both use cases are represented by three tables, i.e. Foo 1->* FooBar *<-1 Bar, these two cases are treated differently by Entity Framework's automated behavior - and this is very important.
EF only handles the cross table for you if it is a direct many-to-many, e.g.
public class Foo
{
public virtual ICollection<Bar> Bars { get; set; }
}
public class Bar
{
public virtual ICollection<Foo> Foos { get; set; }
}
EF handles the cross table behind the scenes, and you are never made aware of the existence of the cross table (from the code perspective).
Importantly, EF Core does not yet support implicit cross tables! There is currently no way to do this in EF Core, but even if there were, you're not using it anyway, so the answer to your problem remains the same regardless of whether you're using EF or EF Core.
However, you have defined your own cross table. While this is still representative of a many-to-many relationship in database terms, it has ceased to be a many-to-many relationship as far as EF is concerned, and any documentation you find on EF's many-to-many relationships no longer applies to your scenario.
Unattached but indirectly added objects are assumed to be new.
By "indirectly added", I mean you that it was added to the context as part of another entity (which you directly added to the context). In the following example, foo is directly added and bar is indirectly added:
var foo = new Foo();
var bar = new Bar();
foo.Bar = bar;
context.Foos.Add(foo); // directly adding foo
// ... but not bar
context.SaveChanges();
When you add (and commit) a new entity to the context, EF adds it for you. However, EF also looks at any related entities that the first entity contains. During the commit in the above example, EF will look at both the foo and bar entities and will handle them accordingly. EF is smart enough to realize that you want bar to be stored in the database since you put it inside the foo object and you explicitly asked EF to add foo to the database.
It is important to realize that you've told EF that foo should be created (since you called Add(), which implies a new item), but you never told EF what it should do with bar. It's unclear (to EF) what you expect EF to do with this, and thus EF is left guessing at what to do.
If you never explained to EF whether bar already exists or not, Entity Framework defaults to assuming it needs to create this entity in the database.
Saving the new LeagueSessionSchedule object throws an error by Entity Framework Core that it cannot INSERT a duplicate primary key value into the dbo.Teams table. I have no idea why its attempting to add to dbo.Teams table
Knowing what you now know, the error becomes clearer. EF is trying to add this team (which was the bar object in my example) because it has no information on this team object and what its state in the database is.
There are a few solutions here.
1. Use the FK property instead of the navigational property
This is my preferred solution because it leaves no room for error. If the team ID does not yet exist, you get an error. At no point will EF try to create a team, since it doesn't even know the team's data, it only knows the (alleged) ID you're trying to create a relationship with.
Note: I am omitting LeagueSessionSchedule as it is unrelated to the current error - but it's essentially the same behavior for both Team and LeagueSessionSchedule.
TeamSession newTeamSession = new TeamSession()
{
TeamId = team.Id
};
By using the FK property instead of the nav prop, you are informing EF that this is an existing team - and therefore EF no longer tries to (re)create this team.
2. Ensure that the team is tracked by the current context
Note: I am omitting LeagueSessionSchedule as it is unrelated to the current error - but it's essentially the same behavior for both Team and LeagueSessionSchedule.
context.Teams.Attach(team);
TeamSession newTeamSession = new TeamSession()
{
Team = team
};
By attaching the object to the context, you are informing it of its existence. The default state of a newly attached entity is Unchanged, meaning "this already exists in the database and has not been changed - so you don't need to update it when we commit the context".
If you have actually made changes to your team that you want to be updated during commit, you should instead use:
context.Entry(team).State = EntityState.Modified;
Entry() inherently also attaches the entity, and by setting its state to Modified you ensure that the new values will be committed to the database when you call SaveChanges().
Note that I prefer solution 1 over solution 2 because it's foolproof and much less likely to lead to unexpected behavior or runtime exceptions.
String primary keys are undesirable
I'm not going to say that it doesn't work, but strings cannot be autogenerated by Entity Framework, making them undesirable as the type of your entity's PK. You will need to manually set your entity PK values.
Like I said, it's not impossible, but your code shows that you're not explicitly setting PK values:
if(team != null)
{
TeamSession newTeamSession = new TeamSession()
{
Team = team,
LeagueSessionSchedule = leagueSessionSchedule
};
leagueSessionSchedule.TeamsSessions.Add(newTeamSession);
}
If you want your PK's to be automatically generated, use an appropriate type. int and Guid are by far the most commonly used types for this.
Otherwise, you're going to have to start setting your own PK values, because if you don't (and the Id value thus defaults to null), your code is going to fail when you add a second TeamSession object using the above code (even though you're doing everything else correctly), since PK null is already taken by the first entity you added to the table.
This should be really simple but I think I'm having possible issues with my model. I have been working with linq over a year and I should have this simple remove easily done. Please help! It's removing both records from the database when I only want one deleted
I have a database table with these properties.
Email, EmployeeName, StoreId
jsch#m.com,Joe Schneider,9
jsch#m.com,Joe Schneider,8
I need to delete Joe Schneider with storeId 9
So I run this simple query and remove process.
var temp2 = difference[i];
var PersonToRemove = db.Permissions.SingleOrDefault(s => s.EmployeeName == temp2 && s.StoreId == Persons.StoreId);
if (PersonToRemove.EmployeeName != null)
{
db.Permissions.Remove(PersonToRemove);
db.SaveChanges();
}
I am assuming one is going to say, hey your model is not right and don't put the name as a key, but I can't just be changing the model because other parts of the app are based on this model and would cause huge breaks. Could you give me advise how to edit the linq query to not delete both records?
model
[Table("Permissions")]
public class Permissions
{
[Key]
public String EmployeeName { get; set; }
public string Department { get; set; }
public int? StoreId { get; set; }
public String Email { get; set; }
}
[Table("Permissions")]
public class Permissions
{
[Key]
public String EmployeeName { get; set; }
}
The problem is here you are defining a primary key which has no length constraint on it. (MaxLength). This leads to EF generate a column with NVARCHAR(MAX). As mentioned here VARCHAR(MAX) columns are not allowed to be primary key. So correct definition should be like below
[Table("Permissions")]
public class Permissions
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.None)] <--
[MaxLength(255)] // <---
public String EmployeeName { get; set; }
}
Edit: You need to recreate the database in order to associated tables initialized with correct settings.
Edit 2 : Also you may need a DatabaseGenerated(DatabaseGeneratedOption.None) since its not identity column.
you can set Deleted state on individual entity like so:
var temp2 = difference[i];
var PersonToRemove = db.Permissions.SingleOrDefault(s => s.EmployeeName == temp2 && s.StoreId == Persons.StoreId);
if (PersonToRemove.EmployeeName != null)
{
db.Entry(PersonToRemove).State = EntityState.Deleted; // do this instead
db.SaveChanges();
}
EF should then figure out which entity you wanted to delete
UPD
I am assuming you are using EF6 and DB-first approach. I am also assuming you've got your DB context class set up with default convention model builder. It seems EF's default object tracking based on Key will not work as your key is not unique (this is a bigger problem, but I understand you're already aware of that).
You might try circumvent that convention by adding custom model builder configuration like so:
class MyDbContext : DbContext {
public virtual DbSet<Permissions> Permissions {get;set;}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Permissions>().HasKey(p => new { p.EmployeeName, p.StoreId});
}
}
since you didn't share your DbContext definition this is just a snippet but hopefully gives you some ideas to explore.
this is the API reference: https://learn.microsoft.com/en-us/dotnet/api/system.data.entity.modelconfiguration.entitytypeconfiguration-1?view=entity-framework-6.2.0
I've used ASP.Net Identity a couple of times now. On a new project I seem to be having an issue creating a user.
When calling _userManager.Create() I get the following error.
The string '{ Name: IX_UserId, Order: 0 }' was not
in the expected format to be deserialized by the
IndexAnnotationSerializer. Serialized values are expected to have
the format '{ Name: 'MyIndex', Order: 7, IsClustered: True,
sUnique: False } { } { Name: 'MyOtherIndex' }'.
I've tried using the following DbContext, which - apart from the class name - is identical to the DbContext i have in another project, that works
public partial class ISIdentityDbContext : IdentityDbContext<IdentityUser>
{
public ISIdentityDbContext()
: base("ISIdentityDbContext")
{ }
public DbSet<ApplicationUserUserInfoMap> ApplicationUserUserInfoMap { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// asp.net identity - call the tables something else..
modelBuilder.Entity<IdentityRole>().ToTable("ApplicationRoles");
modelBuilder.Entity<IdentityUserClaim>().ToTable("ApplicationUserClaims");
modelBuilder.Entity<IdentityUserLogin>().ToTable("ApplicationUserLogins");
modelBuilder.Entity<IdentityUserRole>().ToTable("ApplicationUserRoles");
modelBuilder.Entity<IdentityUser>().ToTable("ApplicationUser");
}
}
I have tried the following:
using (ISIdentityDbContext context = new ISIdentityDbContext())
{
_userManager = new UserManager<IdentityUser>(new UserStore<IdentityUser>(context));
IdentityUser user = new IdentityUser();
user.UserName = "darren";
_userManager.Create(user, "password");
}
And also, the one I really need to get working as it's extending the ApplicationUser (IdentityUser)
using (ISIdentityDbContext context = new ISIdentityDbContext())
{
_userManager = new UserManager<LegacyApplicationUser>(new UserStore<LegacyApplicationUser>(context));
ApplicationUserUserInfoMap map = new ApplicationUserUserInfoMap();
map.UserGUID = "anIdFromAnotherTable";
LegacyApplicationUser user = new LegacyApplicationUser();
user.UserInfoMap = map;
user.UserName = "darren";
_userManager.Create(user, "password");
}
Where my LegacyApplicationUser is:
public class LegacyApplicationUser : IdentityUser
{
public virtual ApplicationUserUserInfoMap UserInfoMap { get; set; }
}
public class ApplicationUserUserInfoMap
{
public int ID { get; set; }
public string UserGUID { get; set; }
}
I'm totally stumped...no matter whether i rebuild my database to match the standard Identity users or use my extended version i keep getting the same exception shown at the top.
I've likely missed something, though can't figure what....
Any ideas?
Ok - I fixed it!
I was going to remove this question as, as it turns out, it's a very narrow question.
that said, I will leave it in here for anybody else struggling to get EF to play nice with a database that isn't all going through EF.
In our case we have a DB that won't be having EF built against it (it's a very old DB) - but some new parts will be EF'ed; the ASP.Net Identity parts.
It turns out my problem was actually with the __MigrationHistory table.
Once I added a DbInterceptor to my DbContext I could see the actual SQL causing the error.
I removed the entries in the _MigrationHistory table and it all worked.
I have had the same problem
I just create the user without a password then use the password hasher to select the user back out and store it again as a work around. It only fails when i set username and password - i met it in code seeding a database.
I'm working on a project using entity framework and code first. Here are my shortened classes
public class BenefitsForm : IAnnualForm, IAuditable
{
public BenefitsUser UserInfo { get; set; }
public CoverageLevel Medical { get; set; }
}
public class MedicalPlan : IHealthPlan
{
public int Id { get; set; }
public virtual IList<CoverageLevel> CoverageLevels { get; set; }
}
public class CoverageLevel
{
public int Id { get; set; }
public virtual MedicalPlan MedicalPlan { get; set; }
}
There are 4 coverage levels in each MedicalPlan. I already have my coverage levels and medical plans made in the database. However, when I create my BenefitsForm, it creates duplicate entries for the classes (I already have them in the database). How can I prevent it from doing this? Here is a small code snippet to show how it happens.
BenefitsForm form = new BenefitsForm() { UserInfo = new BenefitsUser() };
using(var repo = new CoverageLevelRepository())
{
form.Medical = repo.Retrieve(new NumericKey(formId))); //this retrieves the coveragelevel with the id I want.
}
formRepository.Create(form); // this creates a duplicate med plan and 4 duplicate coverage levels.
formRepository.SaveChanges();
I think because you're retrieving the Medical field from a different context than the one you're saving in -- repo vs. formRepository; formRepository isn't tracking the object created by repo, so it assumes that it's a new object, and thus creates a duplicate entry. For performance reasons, I don't believe Entity Framework will go and insert existence checks for you -- tracking is handled internally by the object context itself; each object is bound to a single object context. Try using the same repository to retrieve the MedicalPlan and write back the new BenefitsForm, and you shouldn't have duplicates.
BenefitsForm form = new BenefitsForm() { UserInfo = new BenefitsUser() };
using(var repo = new Repository())
{
form.Medical = repo.Retrieve(new NumericKey(formId))); //this retrieves the coveragelevel with the id I want.
repo.Create(form); // this creates a duplicate med plan and 4 duplicate coverage levels.
repo.SaveChanges();
}
Instead of formRepository.SaveChanges() please try with to use the SaveChanges with the SaveOptions Enum
Example:
ObjectContext.SaveChanges(
System.Data.Objects.SaveOptions.DetectChangesBeforeSave
);
Please see link for more information http://msdn.microsoft.com/en-us/library/dd395500.aspx
It's possible that using IList<...> instead of ICollection<...> for your one-to-many association is causing it to malfunction. Try changing that. Other than that, it may be code within your CoverageLevelRepository that you did not post. For more info on associations, see this guide