Reputation: 431
Can some One guide me I want primeryKey
of a table as guid
having db generated value on insert.
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid Id { get; set; }
but it's giving error
The seed entity for entity type 'User' cannot be added because there was no value provided for the required property 'Id'.
Here is my actual model classes and DbContxt class:
public class BaseModel
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid Id { get; set; }
[Required]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public DateTime CreatedOn { get; set; } = DateTime.UtcNow;
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public DateTime? UpdatedOn { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public DateTime LastAccessed { get; set; }
}
public class User : BaseModel
{
[Required]
[MinLength(3)]
public string Name { get; set; }
[Required]
[MinLength(3)]
[EmailAddress]
public string Email { get; set; }
[Required]
[MinLength(6)]
public string Password { get; set; }
}
Then in the MyDbContext:
public class MyDbContext: DbContext
{
public MyDbContext(DbContextOptions<MyDbContext> options)
: base(options)
{
}
protected override void OnModelCreating(ModelBuilder mb)
{
base.OnModelCreating(mb);
mb.Entity<User>().HasData(
new User() { Email = "[email protected]", Name = "Mubeen", Password = "123123" },
new User() { Email = "[email protected]", Name = "Tahir", Password = "321321" },
new User() { Email = "[email protected]", Name = "Cheema", Password = "123321" }
);
}
public DbSet<User> User { get; set; }
}
Any help please!
Upvotes: 26
Views: 92706
Reputation: 527
If all you need is getting an automatic value when creating and saving a new entity, you can also do it in the constructor:
public class BaseModel
{
public BaseModel()
{
Id = new Guid();
}
[Key]
public Guid Id { get; set; }
public DateTime CreatedOn { get; set; } = DateTime.UtcNow;
public DateTime? UpdatedOn { get; set; }
public DateTime LastAccessed { get; set; }
}
Upvotes: 2
Reputation: 1101
namespace Microsoft.EntityFrameworkCore
{
using System;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Reflection;
public static class ModelBuilderExtensions
{
public static void SetDefaultValuesTableName(this ModelBuilder modelBuilder)
{
foreach (var entity in modelBuilder.Model.GetEntityTypes().Where(x => x.ClrType.GetCustomAttribute(typeof(TableAttribute)) != null))
{
var entityClass = entity.ClrType;
foreach (var property in entityClass.GetProperties().Where(p => (p.PropertyType == typeof(DateTime) || p.PropertyType == typeof(Guid)) && p.CustomAttributes.Any(a => a.AttributeType == typeof(DatabaseGeneratedAttribute))))
{
var defaultValueSql = "GetDate()";
if (property.PropertyType == typeof(Guid))
{
defaultValueSql = "newsequentialid()";
}
modelBuilder.Entity(entityClass).Property(property.Name).HasDefaultValueSql(defaultValueSql);
}
}
}
}
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.SetDefaultValuesTableName();
}
Upvotes: 1
Reputation: 59
modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityRole", b =>
{
b.Property<string>("Id").HasMaxLength(36)
.ValueGeneratedOnAdd();
});
Upvotes: 1
Reputation: 571
Rather than manually updating the migration, you could also implement an update in the OnModelCreating that adds it into the migration for you, e.g.
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
// guid identities
foreach (var entity in modelBuilder.Model.GetEntityTypes()
.Where(t =>
t.ClrType.GetProperties()
.Any(p => p.CustomAttributes.Any(a => a.AttributeType == typeof(DatabaseGeneratedAttribute)))))
{
foreach (var property in entity.ClrType.GetProperties()
.Where(p => p.PropertyType == typeof(Guid) && p.CustomAttributes.Any(a => a.AttributeType == typeof(DatabaseGeneratedAttribute))))
{
modelBuilder
.Entity(entity.ClrType)
.Property(property.Name)
.HasDefaultValueSql("newsequentialid()");
}
}
}
Upvotes: 11
Reputation: 205939
The problem you are experiencing is not specific for autogenerated Guids. The same happens for any autogenerated key values, including the commonly used auto increment (identity) columns.
It's caused by a specific Data Seeding (HasData
) requirement:
This type of seed data is managed by migrations and the script to update the data that's already in the database needs to be generated without connecting to the database. This imposes some restrictions:
- The primary key value needs to be specified even if it's usually generated by the database. It will be used to detect data changes between migrations.
- Previously seeded data will be removed if the primary key is changed in any way.
Note the first bullet. So while for normal CRUD your PK will be auto generated, you are required to specify it when using HasData
fluent API, and the value must be constant (not changing), so you can't use Guid.NewGuid()
. So you need to generate several Guids, take their string representation and use something like this:
mb.Entity<User>().HasData(
new User() { Id = new Guid("pre generated value 1"), ... },
new User() { Id = new Guid("pre generated value 2"), ... },
new User() { Id = new Guid("pre generated value 3"), ... }
);
Upvotes: 27
Reputation: 152
You can use defaultValueSql: "newid()"
in your Code First Migration file.
For Example;
public override void Up()
{
CreateTable(
"dbo.ExampleTable",
c => new
{
Id = c.Guid(nullable: false, identity: true, defaultValueSql: "newid()"),
RowGuid = c.Guid(nullable: false, defaultValueSql: "newid()"),
})
.PrimaryKey(t => t.Id);
}
Upvotes: 8
Reputation: 32159
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
on GUID field works on Entity Framework 6.x, may be not in EF Core yet!
So the solution is:
1) First write your BaseModel
class as follows:
public class BaseModel
{
[Key]
public Guid Id { get; set; }
public DateTime CreatedOn { get; set; } = DateTime.UtcNow;
public DateTime? UpdatedOn { get; set; }
public DateTime LastAccessed { get; set; }
}
2) Then OnModelCreating()
method in your DbContext
should be as follows:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<YourEntity>().Property(x => x.Id).HasDefaultValueSql("NEWID()");
modelBuilder.Entity<User>().HasData(
new User() { Id = Guid.NewGuid(), Email = "[email protected]", Name = "Mubeen", Password = "123123" },
new User() { Id = Guid.NewGuid(), Email = "[email protected]", Name = "Tahir", Password = "321321" },
new User() { Id = Guid.NewGuid(), Email = "[email protected]", Name = "Cheema", Password = "123321" }
);
}
Now create a brand new migration and update the database accordingly. Hope your problem will be solved!
Upvotes: 17
Reputation: 2689
GUID
is handled by Identity framework
and not by EF, so to use GUID you need to do as the following
[Key]
public Guid Id { get; set; }
and then prepare the model before insert into table
new User() { Id = Guid.NewGuid(), Email = "[email protected]", Name = "Mubeen", Password = "123123" },
Upvotes: 4