I am trying to use EF Core 3.0 migrations with a hybrid of an existing tables and new tables built with code first. To prevent the scaffolding of the existing tables I would like to decorate the model class with an attribute (fluently or annotations) so that the migration code generation for those tables is skipped but the model is still built into the DbContext class.
The approach I'm taking is to add the following lines to OnConfiguring
optionsBuilder.ReplaceService<IMigrationsSqlGenerator, SkipMigrator>();
And then creating a SkipMigrator with the following code
public class SkipMigrator:SqlServerMigrationsSqlGenerator
{
public SkipMigrator(
MigrationsSqlGeneratorDependencies dependencies,
IMigrationsAnnotationProvider migrationsAnnotations)
: base(dependencies, migrationsAnnotations){}
protected override void Generate(
MigrationOperation operation,
IModel model,
MigrationCommandListBuilder builder)
{
if (operation.FindAnnotation("SkipMigrations")!=null)
{
Console.WriteLine("Skipping table:");
}
else
{
base.Generate(operation,model,builder);
}
}
}
I assumed that the Generate method was what triggered the creation of the migration code file but it never gets called. Id there a different place I should be intercepting the code generation?
If there a different/simpler way to tell migrations to skip tables yet still keep them in my DbContext?
Your means of trying to create your own IMigrationsSqlGenerator was correct, and I've used that approach before to alter the SQL that is generated as part of a migration.
services.AddDbContext<MyDbContext>(opt =>
{
opt.UseSqlServer();
opt.ReplaceService<IMigrationsSqlGenerator, SkipMigrator>();
});
However, as of EF Core 5.0 it's now much easier to exclude specific tables from migrations using the ExcludeFromMigrations() method on a TableBuilder:
public class ReportingContext : DbContext
{
public DbSet<User> Users { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<User>().ToTable(nameof(Users), t => t.ExcludeFromMigrations());
}
}
More info: https://devblogs.microsoft.com/dotnet/announcing-entity-framework-core-efcore-5-0-rc1/#exclude-tables-from-migrations
If there a different/simpler way to tell migrations to skip tables yet still keep them in my DbContext?
Yes, but it requires a different approach.
Instead of using your current DbContext class for creating migrations, create a SecondDbContext class only for the very purpose of creating migrations. This new SecondDbContext class will hold the DbSets<T> that you want EF to do its migrations on.
Then simply specify the second context when calling add-migration UpdateTable -c SecondDbContext and then update-database -c SecondDbContext.
I'm trying to use EF6 in my project and I've got two databases I'm trying to interact with. My app.config has connection strings for both, and I have two DbContext classes that pass in the app.config's key for the corresponding connection string. One context:
public LogProcessorContext() : base("LogProcessorDb")
{
}
public DbSet<LogFile> LogFiles { get; set; }
the other context:
public MessageTrackingContext() : base("MessageTrackingDb")
{
}
public DbSet<JournalLog> JournalLogs { get; set; }
but when I add the migration using add-migration NewBranch and update the db, a log file table gets added to the message tracking db (the wrong one), and the journallogs table doesn't get added at all. If anyone has any experience getting ef to play nice with multiple db/contexts, i'm all ears. I'm sure its just some simple mistake I'm making.
btw,
"LogProcessorDb"
and
"MessageTrackingDb"
are the keys in my app.config for my connection strings.
Thanks!
I am getting into the Entity Framework, but I am unsure if I am missing a critical point in the code-first approach.
I am using a generic repository pattern based on the code from https://genericunitofworkandrepositories.codeplex.com/ and have created my entities.
But when I try to access or modify the entity I run into the following:
System.InvalidOperationException: The entity type Estate is not part
of the model for the current context.
It happens when I am trying to access it from my repository:
public virtual void Insert(TEntity entity)
{
((IObjectState)entity).ObjectState = ObjectState.Added;
_dbSet.Attach(entity); // <-- The error occurs here
_context.SyncObjectState(entity);
}
The database (./SQLEXPRESS) is created just fine, but the entities (tables) is just not created on startup.
I am wondering if I need to explicit set the mapping of the entities? Is EF not able to this by its own?
My Entity is:
public class Estate : EntityBase
{
public int EstateId { get; set; }
public string Name { get; set; }
}
My context is as so:
public partial class DimensionWebDbContext : DbContextBase // DbContextBase inherits DbContext
{
public DimensionWebDbContext() :
base("DimensionWebContext")
{
Database.SetInitializer<DimensionWebDbContext>(new CreateDatabaseIfNotExists<DimensionWebDbContext>());
Configuration.ProxyCreationEnabled = false;
}
public new IDbSet<T> Set<T>() where T : class
{
return base.Set<T>();
}
}
Is there any specific reason why this error occurs? I have tried enable migrations and enable automatic migrations without any help either.
Put this in your custom DbContext class:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Estate>().ToTable("Estate");
}
If your tables are not created on startup, this is why. You need to tell the DbContext about them in the OnModelCreating method override.
You can either do custom per-entity mappings here, or separate them out into separate EntityTypeConfiguration<T> classes.
Apparently, this error is very generic, it could have a number of reasons. In my case, it was the following: The connection string (in Web.config) generated by the .edmx was invalid. After almost a day of trying everything, I changed the connection string from the EF string to an ADO.NET string. This solved my issue.
For example, the EF string looks something like this:
<connectionStrings>
<add name="BlogContext"
connectionString="metadata=res://*/BloggingModel.csdl|
res://*/BloggingModel.ssdl|
res://*/BloggingModel.msl;
provider=System.Data.SqlClient
provider connection string=
"data source=(localdb)\v11.0;
initial catalog=Blogging;
integrated security=True;
multipleactiveresultsets=True;""
providerName="System.Data.EntityClient" />
</connectionStrings>
And the ADO.NET string looks like this:
<connectionStrings>
<add name="BlogContext"
providerName="System.Data.SqlClient"
connectionString="Server=.\SQLEXPRESS;Database=Blogging;
Integrated Security=True;"/>
</connectionStrings>
Source: http://msdn.microsoft.com/nl-nl/data/jj556606.aspx
For me the issue was that I had not included the Entity Class within my db set inside the context for entity framework.
public DbSet<ModelName> ModelName { get; set; }
You may try removing the table from the model and adding it again. You can do this visually by opening the .edmx file from the Solution Explorer.
Steps:
Double click the .edmx file from the Solution Explorer
Right click on the table head you want to remove and select "Delete from Model"
Now again right click on the work area and select "Update Model from Database.."
Add the table again from the table list
Clean and build the solution
The problem may be in the connection string. Ensure your connection string is for SqlClient provider, with no metadata stuff related to EntityFramework.
My issue was resolved by updating the metadata part of the connection string. Apparently it was pointing at the wrong .csdl / .ssdl / .msl reference.
I've seen this error when an existing table in the database doesn't appropriately map to a code first model. Specifically I had a char(1) in the database table and a char in C#. Changing the model to a string resolved the problem.
One other thing to check with your connection string - the model name. I was using two entity models, DB first. In the config I copied the entity connection for one, renamed it, and changed the connection string part. What I didn't change was the model name, so while the entity model generated correctly, when the context was initiated EF was looking in the wrong model for the entities.
Looks obvious written down, but there are four hours I won't get back.
For me the issue was that I used the connection string generated by ADO.Net Model (.edmx). Changing the connection string solved my issue.
This can also occur if you are using a persisted model cache which is out of date for one reason or another. If your context has been cached to an EDMX file on a file system (via DbConfiguration.SetModelStore) then OnModelCreating will never be called as the cached version will be used. As a result if an entity is missing from your cached store then you will get the above error even though the connection string is correct, the table exists in the database and the entity is set up correctly in your DbContext.
The message was pretty clear but I didn't get it at first...
I'm working with two Entity Framework DB contexts sysContext and shardContext in the same method.
The entity I had modified\updated is from one context but then I tried to save it to the other context like this:
invite.uid = user.uid;
sysContext.Entry(invite).State = EntityState.Modified;
sysContext.SaveChanges(); // Got the exception here
but the correct version should be this:
invite.uid = user.uid;
shardContext.Entry(invite).State = EntityState.Modified;
shardContext.SaveChanges();
After passing the entity to the correct context this error went away.
I was facing the same issue with EntityFrameworkCore trying to update a range of values.
This approach did not work
_dbSet.AttachRange(entity);
_context.Entry(entity).State = EntityState.Modified;
await _context.SaveChangesAsync().ConfigureAwait(false);
After adding UpdateRange method and removing attach and entry everything work
_dbSet.UpdateRange(entity);
await _context.SaveChangesAsync().ConfigureAwait(false);
Sounds obvious, but make sure that you are not explicitly ignoring the type:
modelBuilder.Ignore<MyType>();
map of the entity (even an empty one) added to the configuration will lead to having the entity type be part of the context. We had an entity with no relationship to other entities that was fixed with an empty map.
if you are trying DB first then be sure that your table has primary key
Visual Studio 2019 seems to cause this for me. I fixed it by generating the edmx model again in 2017.
For me it was caused because I renamed the entity class.When I rolled it back it was Ok.
I had this
using (var context = new ATImporterContext(DBConnection))
{
if (GetID(entity).Equals(0))
{
context.Set<T>().Add(entity);
}
else
{
int val = GetID(entity);
var entry = GetEntryAsync(context, GetID(entity)).ConfigureAwait(false);
context.Entry(entry).CurrentValues.SetValues(entity);
}
await context.SaveChangesAsync().ConfigureAwait(false);
}
This was in an async method, but I've forgot to put await before GetEntryAsync, and so I got this same error...
Make sure you have set up your mapping class to point to your SQL table
I've had the same problem and in my case, the reason why I got this error message was that the property identifiers in my class file did not match the identifiers defined in the database, e.g. I wrote an identifier with a beginning uppercase letter while in the database it was all lowercase.
I've faced this issue after publishing my project using web deploy. It happened because my the metadata in connection string of my publish profile was not same as connection string in my project because I dropped the edmx for some reason and added it back with different Name. To fix it I had to delete the publish profile and redeploy again so that the metadata matches the names.
With models created from database (First Database), it is not possible to replace the connection string (with metadata and providerName="System.Data.EntityClient", from EDMX) by one of SQL.
The only possibility I have found is to create another context that uses the SQL connection (providerName="System.Data.SqlClient")
<connectionStrings>
<add name="DefaultConnection" providerName="System.Data.SqlClient" connectionString="Max Pool Size=10000;Pooling=true;Data Source=MyIpServer;Initial Catalog=myDatabase;Persist Security Info=True;User ID=MyUser;Password=MyPassword;TrustServerCertificate=False" />
<add name="Entities" providerName="System.Data.EntityClient" connectionString="metadata=res://*/Datos.MyModel.csdl|res://*/Datos.MyModel.ssdl|res://*/Datos.MyModel.msl;provider=System.Data.SqlClient;provider connection string="Max Pool Size=10000;Pooling=true;data source=MyIpServer;initial catalog=myDatabase;persist security info=True;user id=MyUser;password=MyPassword;trustservercertificate=False;MultipleActiveResultSets=True;App=EntityFramework"" />
</connectionStrings>
With the two context options, with Identity:
public partial class ContextWithUsers : IdentityDbContext<MyUser>
{
public ContextWithUsers() : base("name=DefaultConnection")
{
}
}
public class MyUser : IdentityUser
{
// aditional table user data
//public virtual MyUserInfo MyUserInfo { get; set; }
}
Normal context:
public partial class ContextWithoutUsers : DbContext
{
public ContextWithoutUsers () : base("name=Entities")
{
}
}
This solution works, but... Why is it not possible to use the same context with the First Database model + Identity ?
NOTE 1: if you force change connection string show:
System.Data.Entity.Infrastructure.UnintentionalCodeFirstException: 'The context is being used in Code First mode with code that was generated from an EDMX file for either Database First or Model First development. This will not work correctly. To fix this problem do not remove the line of code that throws this exception. If you wish to use Database First or Model First, then make sure that the Entity Framework connection string is included in the app.config or web.config of the start-up project. If you are creating your own DbConnection, then make sure that it is an EntityConnection and not some other type of DbConnection, and that you pass it to one of the base DbContext constructors that take a DbConnection. To learn more about Code First, Database First, and Model First see the Entity Framework documentation here: http://go.microsoft.com/fwlink/?LinkId=394715'
NOTE 2: External Class library with EDMX + Data and ASP.NET webform project
Delete the .edmx file and add it again. Especially, if you have upgraded the Entity Framework.
Could be stupid, but if you only got this error on some Table, dont forget to clean your project and rebuild (could save a lot of time)
If I build an application and let code first figure out where to put the database and the user inserts data via the application, will that data get lost on a click once update ? If so, how do I approach this problem ?
Thanks
No there is No need to "lose" any data when using automatic migrations.
You migration config class should state no data loss allowed
You will need to build custom scripts/ or tweak the generated scripts when dealing with changes that result in data loss.
public override void MigrateDb() {
Database.SetInitializer(new MigrateDatabaseToLatestVersion<MYDbContext, MYSECIALMigrationConfiguration>());
// Context = GetDefaultContext(); // check if a new context is really needed here
Context.Database.Initialize(true);
}
public class MYSPECIALMigrationConfiguration : MYBaseMigrationConfiguration<MYDbContext>{ }
public abstract class MYBaseMigrationConfiguration<TContext> : DbMigrationsConfiguration<TContext>
where TContext : DbContext{
protected MYBaseMigrationConfiguration() {
AutomaticMigrationsEnabled = true; // you can still chnage this later if you do so before triggering Update
AutomaticMigrationDataLossAllowed = true; // you can still chnage this later if you do so before triggering Update
}
how to approach migrations.
.. Thats actual a big question.
EF6 Migrations - new features and options
Great info on Migrations when working in teams.
This covers many scenarios you may recognise and thus help you understand what approach suits you best.
I've added two new properties to my domain model class and two properties to a data table accordingly. Then I tried to launch my mvc web application and got
The model backing the 'EFDbContext' context has changed since the database was created.
Consider using Code First Migrations to update the database
(http://go.microsoft.com/fwlink/?LinkId=238269).
Having read the following posts:
MVC3 and Code First Migrations
EF 4.3 Automatic Migrations Walkthrough
I tried to Update-Database through Package Manager Console, but got an error
Get-Package : Не удается найти параметр, соответствующий имени параметра "ProjectName".
C:\Work\MVC\packages\EntityFramework.5.0.0\tools\EntityFramework.psm1:611 знак:40
+ $package = Get-Package -ProjectName <<<< $project.FullName | ?{ $_.Id -eq 'EntityFramework' }
+ CategoryInfo : InvalidArgument: (:) [Get-Package], ParameterBindingException
+ FullyQualifiedErrorId : NamedParameterNotFound,NuGet.PowerShell.Commands.GetPackageCommand
The EntityFramework package is not installed on project 'Domain'.
But the Entityframework is installed on project Domain. I removed it from references, deleted package.config and sucessfully reinstalled EF. But Update-Database still returns same error. Update-Database -Config does as well
What am I doing wrong?
EDIT
Many thanks to Ladislav Mrnka, I'll try to rephrase my question. As far as I changed my data table manually, I am not expected to use migration. But how can I now make EF work with manually edited domain model class and data table?
Try to add this to startup of your application (you can put it to App_Start):
Database.SetInitializer<EFDbContext>(null);
It should turn off all logic related to handling the database from EF. You will now be fully responsible for keeping your database in sync with your model.
I had the same problem and this is how I fixed the issue.
I dropped table __MigrationHistory using sql command and run the update-database -verbose again.
Apparently something was wrong with this automatic created table.
Answer 2 was exactly what was needed. Although when I got to the App_Start I realized that there were 4 configuration files and didn't see where this would fit in any of them. Instead I added it to my EF database context
namespace JobTrack.Concrete
{
public class EFDbContext : DbContext
{
//Set the entity framework database context to the connection name
//in the Webconfig file for our SQL Server data source QSJTDB1
public EFDbContext() : base("name=EFDbConnection")
{
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//Remove the tight dependency on the entity framework that
//wants to take control of the database. EF by nature wants
//to drive the database so that the database changes conform
//to the model changes in the application. This will remove the
//control from the EF and leave the changes to the database admin
//side so that it continues to be in sync with the model.
Database.SetInitializer<EFDbContext>(null);
//Remove the default pluaralization of model names
//This will allow us to work with database table names that are singular
base.OnModelCreating(modelBuilder);
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
}
//Allows for multiple entries of the class State to be used with
//interface objects such as IQueryTables for the State database table
public DbSet<State> State { get; set; }
}
}