I have a local database that is currently in it's second version and should now go to it's third version.
The code for the previous migrations was generated by another programmer so I am assuming I am doing something wrong here.
In my model there are around 30 classes, and inside the model folder there is a mapping folder and it contains the mappings for those 30 classes.
So now I added 1 new class in the same manner as those previous classes and then run the add-migration command in the Package Manager Console.
Infortunately I get an empty migration Up() and Down() method.
When I look in the database there is a __migrationHistory available with the previous 2 migrations. If I run my application now, the third migration is also added but obviously the new table is not being created because it's not in the Up() method.
What could I be doing wrong?
I think something is going wrong when scaffolding the previous migrations... It's like it can't find the new Code-First classes I have added.
This is my command:
add-migration "1.2" -verbose -ProjectName "MyEFproject"
I am assuming that the scaffolding doesn't know where to look for the new class... or is this by convention that all model classes are just expected to be in the project?
Result of add-migration:
namespace MyProject.Migrations
{
using System;
using System.Data.Entity.Migrations;
public partial class _1002 : DbMigration
{
public override void Up()
{
}
public override void Down()
{
}
}
}
Sample of new Model Class:
using System;
using System.Collections.Generic;
namespace MyProject.Models
{
public partial class MyTable
{
public string SomeId { get; set; }
public string SomeText { get; set; }
}
}
Sample of new Mapping class
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration;
namespace MyProject.Models.Mapping
{
public class MyTableMap : EntityTypeConfiguration<MyTable>
{
public MyTableMap()
{
// Primary Key
this.HasKey(t => t.SomeId);
// Properties
this.Property(t => t.SomeText)
.IsRequired()
.HasMaxLength(30);
// Table & Column Mappings
this.ToTable("MyTable", "database");
this.Property(t => t.SomeId).HasColumnName("SomeId");
this.Property(t => t.SomeText).HasColumnName("SomeText");
}
}
}
Thank you,
You need to add your table to your implementation of the DbContext class, e.g.
public class MyDatabaseEntities : DbContext {
public virtual DbSet<MyTable> MyTable { get; set; }
}
While rolling back an existing EF Core Data Context back to empty, my migrations wouldn't generate until I removed the ApplicationDbContextModelSnapshot that accompanied the migrations.
This class is auto-generated and needs to align with your current migration level.
I was able to fix this issue by deleting a record of last migration from _MigrationHistory table.
This record had been incorrectly created before I added DbSet for new model object to DbContext class.
After this deletion new migration was created with correct Up() and Down() methods.
I had this problem because I forgot to add {get; set;} after my variable names
You need to add your table to your implementation of the DbContext class, e.g. While rolling back an existing EF Core Data Context back to empty, my migrations wouldn't generate until I REMOVED the ApplicationDbContextModelSnapshot that accompanied the migrations.
In my case, the datacontext project is a class lib project. It is different from the startup project which is asp.net mvc 5 project. Now by mistake the connection string in the startup project is pointing to a different database.
So ensure that datacontext project and startup project point to the same database. Also use the full command as mentioned in the question like the following. You can include -Force as well.
add-migration "InitialMigration" -verbose -ProjectName "MyEFproject" -Force
Also: Make sure any new properties you've added are public!
In my case I was doing a migration where I added fields to an existing table and was ending up with empty Up and Down methods,
I had something like this:
public bool ExistingField { get; set; }
bool NewField { get;set; }
Can you spot the difference...?
If you make this mistake rerun the migration with the same name (you probably will need to add the -Force parameter to scaffold it full).
PS. Always make sure your project builds fully before attempting to do any kind of EF command. If your project doesn't already build you're asking for trouble.
You need to add your MyTable in Dbset and your issue will be resolved:
public DbSet<MyTable> MyTables { get; set; }
I was getting empty migrations added when I had mistakenly related two tables using a 1-many relationship rather than a many-many (i.e. i forgot one of the navigation properties). I had a seeding file that was expecting a many-many relationship and was subsequently failing during the migration causing the migration to fail. Unfortunately there was no output that made it obvious that was the problem and it was only by using the Entity Framework Power Tools (v4 but installed in VS2015) did i visually see the incorrect relationship and realize it was probably the cause.
I had to Update-Database with the latest migration before the empty one appending this parameter -TargetMigration:"{your-migration-name}".
Probably it will tell you that there will be data loss from the next buggy one we tried. If you can afford it append -Force to it.
Then I tried to add my new Add-Migration and it wasn't empty.
Final thing that you may need to do if above is throwing exception is to go SQL Server Management Studio and delete the last Automatic migration and try to add it again.
if new tables added to Context
just remove new table in "Migration/ExampleContextModelSnapshot"
I had the same issue on EFcore. When renaming Phone -> mobile, the migration came up empty.
My DbContext :
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<MyUser>()
.Property(c => c.Mobile)
.HasColumnName("phone");
}
Problem was using .HasColumnName("phone") was overriding the actual property name so EF probably couldn't see any change.
Changing string value made it work.
I had this exact issue after I wanted to add an extra column to my database. Because my data would not seed unless the tables were empty, I deleted all the tables and the migrations to recreate the tables. When I tried to migrate, the migration had empty up and down methods.
I solved this by deleting the snapshot file as this was creating the issue. So I deleted all the migrations and the snapshot file, added the migration again and ran update database. The tables and migrations were successfully updated with my new column.
A better way to do this though is to run the down method and drop the tables like that if you are working on test data. Obviously this is bad in the real world to drop tables.
To me the problem was that Id property that should correspond to table id was named FeedbackId.
I changed to "Id" and then Up/Down weren't empty anymore.
Dunno if that can help somehow
If your project is small, i.e. you do not have too many migrations yet, you can delete all from your Migration folder. After that, add the migrations again.
I think this also happens when u try to do migration without any changes in the models. eg when you do migration one and succeed, when u try to do migration2 without doing any changes in any of the models, it will create empty UP and Down.
From the perspective of a complete Entity Framework (Core) beginner:
Create your class which will become your table
You can have subclasses with many-to-many or one-to-one relationships.
In step 3 you see the context where both properties have a one-to-one relationship.
Ensure you have one DbContext
If you have more than one DbContext you need to specify which context you want to add the migration to with the -Context parameter.
Add your class to your DbContext as shown by #CondingIntrigue
As a reference The Entity Framework Core DbSet
public class AccountContext : DbContext
{
public DbSet<Account> Accounts { get; set; }
public DbSet<SecretIdentity> SecretIdentity { get; set; }
}
Enter Add-Migration
In my case, I was encountering similar problems with Visual Studio Code.
I have fixed these by doing the following:
Check inside your ContextModelSnapshot : ModelSnapshot
Comment Model Entity Definition…
Delete your migration files related to these entity
Delete the migrations from the dbo.__EFMigrationsHistory table
Compile your solution.
Run the following commands:
dotnet ef migrations add migrationName -p ProjectContainer/
dotnet watch run
Temprorary remove
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
}
and then do initial create
Add-Migration InitialCreate
If after adding your class in the dbContext and your migration is still empty: do the following:
In your DbContextModelSnapshot class, remove every related code to that class name that you are trying to apply add-migration on. Save the DbContextModelSnapshot.cs and use the Add-Migration "Added_filename"
This work for me.
In my case ,I deleted Migration folder completely. As long as I didn't remove the "ApplicationDbContextModelSnapshot" and all previous migrationas it didn't work.
For me it was because I hadn't add Configuration files.
onModelCreating:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.ApplyConfigurationsFromAssembly(typeof(AppDbContext).Assembly);
}
and add configurations in same assembly derived from IEntityTypeConfiguration<T> where T is your model.
I missed adding
{get;set}
After adding getter and setter, up and down methods are not empty.
Related
Im trying to make PhoneNumber nullable for my IdentityUser model, but its not working. I have this User class
public class User : IdentityUser<Guid>
{
...props
}
I tried adding it in my Context like:
public class DbContext: IdentityContext<User, Role, Guid>
{
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
ConfigureUserTable(builder);
}
private void ConfigureUserTable(ModelBuilder builder)
{
builder.Entity<User>
.Property(x => x.PhoneNumber)
.IsRequired(false);
}
}
but when I created a new migration, nothing changed in the new migration.
Also tried to override like:
public class User : IdentityUser<Guid>
{
public override string? PhoneNumber { get; set; }
...props
}
But still nothing in the new migration.
How can I make PhoneNumber optional on DB without creating a new migration and updating the field by writing explicit SQL?
It seems like the problem was that someone went and made the column on DB not nullable manually. Because of that, nothing new was generated when I was running migrations.
Based on your answer, it looks like you had a situation related to your environment. In case you are new to migrations, it's SUPER important that you don't make direct database modifications to any tables handled by EF Migrations. You can get naming conventions out of sync, or in your case, migrations that just don't appear to do what you need to.
Entity Framework, although appears like it "checks to see if the model matches", what it's really doing is checking to see if the last applied migration matches the ones it thinks it needs to run. To Date, I don't think there is a way to have EF validate every single field during a migration add.
Just something to be aware of. If you have DBAs who don't want modifications made directly, use the new migration bundles for deployment or script them.
Deployments of EF Migrations Reference
I am using entity framework to attach to an existing database where I will add a few more tables. Someone on here said this is not possible and I would need to keep the new tables separate in a new database. Here is that question:
Do not create existing table during Migration
I did some more investigation and found this on MSDN:
https://msdn.microsoft.com/en-us/data/dn579398.aspx
According to this I should run an initial migration like this:
add-migration initial -ignorechanges
so I did that and that is supposed to look at the database and match it up. After I update the database, then I am supposed to add another migration without the -ignorechanges. When I do the second migration, I get this:
namespace PTEManager.Domain.Migrations
{
using System;
using System.Data.Entity.Migrations;
public partial class second : DbMigration
{
public override void Up()
{
}
public override void Down()
{
}
}
}
so it is not trying to add the 2 new tables and relationships that I need. It is coming up blank. I have tried deleting the _migrationhistory table from the database and starting over but still nothing. What am I missing?
It sounds like you are adding the second migration without making any changes. What you need to do is this:
Add DBSet<ModelName> properties to your context for all existing
tables.
Create the initial migration using -ignorechanges
Add DBSet<ModelName> properties to your context for all new tables.
Create the second migration as normal.
The second migration should then contain code to create only the new tables, relationships etc. you want. It doesn't matter whether you update the database in between migrations or only once at the end.
You could try to add normal migration and modify Up/Down methods so they include only the 2 new tables.
look at this question for example.
Entity Framework (EF) Code First Cascade Delete for One-to-Zero-or-One relationship
I have a normal context etc.
If i change anything, i can generate a new migration per Add-Migration test.
But if i change WillCascadeOnDelete() from true to false or adding some with true it is ignored by entity framework.
I'm using Code first with a generated model from database.
In the generated model everything was on WillCascadeOnDelete(false).
So now I'm changing it from false to true but its ignored by entity framework.
I tried this: http://msdn.microsoft.com/en-us/data/jj591620.aspx#CascadeDelete too.
After adding this lines ... Nothing changes if i add Add-Migration newTest.
modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>()
modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>()
This is ignored, too, by Add-Migration thirdTest.
modelBuilder.Conventions.Add<OneToManyCascadeDeleteConvention>()
modelBuilder.Conventions.Add<ManyToManyCascadeDeleteConvention>()
I can change everything with WillCascadeOnDelete... It is ignored!
If i change everything else, it works and would be appended in new Migrations...
The main class for this construct is the following.
[Table("SomeToThing")]
public class SomeToThing : Base
{
[Column("Some")]
public Guid SomeId { get; set; }
[ForeignKey("SomeId")]
public virtual Some Some { get; set; }
[Column("Thing")]
public Guid ThingId { get; set; }
[ForeignKey("ThingId")]
public virtual Thing Thing { get; set; }
}
I have this tables:
Some
SomeToThing
Thing
The SomeToThing has additional variables and because that i can't map Some directly to Thing.
I know this thread is old, but I was just having the same issue.
My solution was to delete the migration source file and re-scaffolding it from scratch.
On my first try I forgot to set .WillCascadeOnDelete(false), and for good reasons, SQL Server rejected the migration due to cycles. Then when I tried to re-scaffold the migration using the same name after removing cascades in the OnModelCreating method, EF just wouldn't pick up those particular changes.
Then I deleted the migration source file and ran Add-Migration SameMigrationName. Cascade deletes were removed, and seems like it worked, since MSSQL accepted the migration script. I'm using EF 6.1.3 btw.
One thing I would like to mention, relating to the problem I was having, was that I added the following code (to my 'OnModelCreating', ie DbContext):
modelBuilder.Entity<MyEntityTwo>()
.HasMany(e => e.MyEntityOne)
.WithRequired(e => e.MyEntityTwo)
.HasForeignKey(e => e.MyEntityTwoId)
.WillCascadeOnDelete(false);
but I added this AFTER the table defining MyEntityOne was already defined, ie in a previous migration.
Turns out that since I added this to OnModelCreating after the table was already defined, entity framework did 'not' pickup the willcascadeondelete(false) when I added a new migration.
To fix this, I had to manually add the following to (new) migration:
DropIndex(...this was created by EF for me already. Not important...);
DropForeignKey("MyEntityOne", "<name of Foreign key goes here ie FK_MyEntityOne_...etc>");
AddForeignKey("MyEntityOne", "MyEntityTwoId", "MyEntityTwo", "Id", cascadeDelete:false);
AlterColumn(...this was created by EF for me already. Not important...);
CreateIndex(...this was created by EF for me already. Not important...);
By adding the AddForeignKey line, with cascadeDelete: false, it will re-apply the foreign key with cacade on delete false this time.
I have a DbContext with many classes/entities targeting a Firebird database. I used to have an entity named DinnerPasses, which was declared (as all others) using Code First:
public class FreezedOrdersContext : DbContext
{
public FreezedOrdersContext()
: base("name=ConnectionString")
{
}
// The deleted entity... (NOTE: THIS IS NO LONGER IN THE FILE...)
public virtual DbSet<DinnerPass> DinnerPasses { get; set; }
public virtual DbSet<FirebirdFreezedSalesOrder> FreezedSalesOrders { get; set; }
// Other entities, removed for clarity...
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
Database.SetInitializer<FreezedOrdersContext>(null);
// Some of the lines still in the file...
modelBuilder.Entity<FirebirdFreezedSalesOrder>().HasKey(p => new { p.ORDERTYPE, p.CUSTOMERTYPE, p.TABLEID, p.SUBORDERNUMBER });
modelBuilder.Entity<FirebirdFreezedSalesOrder>().ToTable("FREEZEDSALESORDER");
// NOTE: This 2 lines are NO LONGER in the file...
modelBuilder.Entity<DinnerPass>().HasKey(p => p.NUMBER);
modelBuilder.Entity<DinnerPass>().ToTable("GENERALINFO");
}
}
The DinnerPasses entity was deleted. Now, reading any of the other entities goes fine, but when I try to save some other entities into the database db.SaveChanges();, I get the following exception:
"Dynamic SQL Error SQL error code = -204 Table unknown DinnerPasses At line 6, column 8"
System.Exception {FirebirdSql.Data.FirebirdClient.FbException}
So, I guess that EF created some model file somewhere that allows it "remember" that entity (and since the line modelBuilder.Entity<DinnerPass>().ToTable("GENERALINFO"); is no longer part of the file, it is trying to get the DinnerPass entity from a table of the same name).
How can I fix this? Where are the model files for this? They are certainly not found anywhere in my project folder...
Thanks in advance.
You need to remove the DbSet and the entity class from your context entirely (including references from other entities!). If you don't specify any additional metadata, then Entity Framework will assume a tablename derived from the entity classname.
Ok, so I found out what happened:
I removed the DinnerPasses entity and replaced it with a new entity called GeneralInfo that was more appropriate (it gets more info from the table, instead of my initial needs that was the Dinner Pass information within that table).
Here is the issue: When I created the new GeneralInfo class, I copied a property from the old DinnerPass class (called FormattedDinnerPasses) into the new GeneralInfo class/entity. When I changed that property to a method, it no longer tried to access the "DinnerPasses" table.
So, I think the problem was having a property that didn't have a backing variable (the property just did a bunch of calculations and returned a list of formatted items). Maybe you can have one but need to give it an attribute indicating that it must be ignored when Entity Framework is binding to the table...
Im unable to scaffold a controller (MVC5 Controller with views, using Entity Framework) in Visual studio 2013 (update 3 and 4). The error message is below:
There was an error running the selected code generator:
A configuration for type 'Library.Morthwind.Models.Catgeory' has already been added. To reference the existing configuration use the Entity<T>() or ComplexType<T>() methods
I have created the models by selecting 'Reverse Engineer Code First' from the 'Entity Framework Power Tools Beta 4' Tool menu.
Any ideas about what might cause this error?
I had the same issue today.
I had added some custom configuration for one of my Model classes to add a relationship using the fluent API. This was specified in my dbContext class in the OnModelCreating override using the following:
modelBuilder.Configurations.Add(new OrderConfiguration());
Commenting out the above line allowed the Controller scaffolding to run as expected.
VS 2013 update 2 had a problem with this and the scaffolding came up with an unhelpful error with no further information. In installed Update 3 and it gave just enough detail to track down the underlying issue.
Jeff.
I've been having this issue too. Jeff's solution works in some cases. But as my DbContext grew with more models that had keys needing to be mapped I couldn't delete the Configurations.Add() methods because I would then get errors that EF couldn't find primary keys, etc...
I did discover that by changing my DBContext derived class to use IDbSet properties instead of DbSet I could generate the controllers and views just fine. However, for me this introduced another issue, IDbSet does not support the async methods.
It appears I can either generate non-async controllers with configurations in place or async methods without configuration classes.
If your context properties are of type DbSet, try changing them to IDbSet. If you aren't generating async controller methods this may work for you.
I also had the same issue and changing my context class to use IDbSet allowed me to successfully use the scaffolding to create a new controller. But since I didn't want to give up the async methods I changed the context back to use DbSet and that worked for me.
Here is how I resolved this issue.
I have Visual Studio 2013 Update 4.
I use EF Power Tools.
Comment out all of the DbSet < ... >
Inside OnModelCreating, only leave the object you are scaffolding:
modelBuilder.Configurations.Add(new SomeTableDataMap());
At the bottom of my context class I did notice this got created:
public System.Data.Entity.DbSet SomeTableDatas{ get; set; }
Oh: I also put this in my constructor but it's for something else,
this.Configuration.LazyLoadingEnabled = false;
Seriously, this worked today, I've tried all of these solutions nothing worked for Update 4. I had this working in Update 2 and Update 3 using previous solutions. This is the most up-to-date solution for now.
Simple workaround that worked for me (after trying many other solutions suggested here and other places in vain...).
In the scaffolding dialog I just added a new DataContext e.g. TempContext. All the scaffolding worked as expected and then I could simply move the generated code in TempContext into my original DbContext and renamed the TempContext in the generated controllers to the original DbContext.
There are already multiple workarounds posted for this issue. And in this comment, I will try to provide the underlying issue why this may be failing. [With the hope to make people aware of the root cause]
Let's say, you have a DbContext (to be specific, child class of DbContext) in your application, and you are trying to use a model class (let's say Model) and the DbContext and scaffolding controllers / views.
I am guessing that the DbContext did not have a "DbSet< Model > Models {get; set;}" property on it but the DbSet was nevertheless added to the DbContext using code in OnModelCreating method.
In the above case, scaffolding first tries to detect DbSet property on DbContext (by reflection only - so that does not detect if OnModelCreating has code to add the DbSet) and given it's not, scaffolding adds a DbSet property to the DbContext and then tries to scaffold using that DbContext , however when running the scaffolding, we create an instance of DbContext and we also call OnModelCreating , and at that point, scaffolding fails because there are multiple DbSet types with the same model in the DbContext (one added by scaffolding and one configured in code in OnModelCreating).
[This happens not only for the model being used but also for related models in that model , scaffolding adds DbSet properties for all related models]
[Also, one doesn't see the added DbSet's after the scaffolding is done because scaffolding rolls back any changes if the operation did not complete successfully, like Jeff mentioned , the error message was poor initially and was improved to give some hint to the user but it's still not super clear what's going on]
This is a bug in scaffolding , a simple work around would be to use DbSet property on DbContext for all related models of your model class instead of configuring them in OnModelCreating.
I was getting a different error when trying to scaffold a controller with CRUD actions and views. In my case it was saying:
"There was an error running the selected code generator. Object instance
not set to an instance of the object."
The problem was hard to find: I created a table in SQL Server but forgot to set the Primary Key for the table. Setting the Primary key and updating Entity Framework's .edmx file solved the problem.
Hope it helps.
None of the rest of the answers worked for me. What I found out was that the issue only happened when scaffolding and adding Configurations using the Fluent API. So what I did was, instead of having separated files, each one having an Entity Configuration like this:
public class ApplicationUserMapConfiguration : EntityTypeConfiguration<ApplicationUserMap>
{
public ApplicationUserMapConfiguration()
{
ToTable("ApplicationUserMap", "Users");
HasKey(c => c.Id);
}
}
And then adding this configuration to the DbContext:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Configurations.Add(new ApplicationUserMapConfiguration());
}
I just added the whole configuration inside the DbContext for every entity:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
//ApplicationUser
modelBuilder.Entity<ApplicationUser>().HasKey(c => c.Id);
modelBuilder.Entity<ApplicationUser>().ToTable("ApplicationUser", "Usuario");
//Other entities...
}
Now I can scaffold perfectly. I already submited and issue on the Mvc GitHub.
Also, if another error message raises up saying:
There was an error running the selected code generator: ‘Exception has been thrown by the target of an invocation.’
You should modify your DbContext constructor to:
public YourDbContext() : base("YourDbContext", throwIfV1Schema: false) { }
None of answers of this post worked for me. I handled this issue creating new context class through plus button in Add Controller scaffolding dialog. Once VS created controller and views, I just remove the created context class and change the the generated controller code to use my existing context class.
Important: This process will add a new connection string for the new context, dont forget to remove it as well.
mine got fixed like this:
public virtual DbSet<Category> Categories { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//--> EntityTypeConfiguration<Your Model Configuration>
modelBuilder.Configurations.Add(new EntityTypeConfiguration<CategoryMapping>());
base.OnModelCreating(modelBuilder);
}
DOn't forget Ctrl + Shift + B so your code compile (i'm not sure for single solution, but since mine is in another project in same solution, it should get compiled first)
I solved it by adding a try/catch on the code to OnModelCreating function inside the context class.
Just keep the
base.OnModelCreating(modelBuilder);
outside your try/catch