I have a migration seed data that I wish to run when OnModelCreating
method runs in my application.
Part of the data are for these two entities - State
and LGA
and so I have these two lines in addition to others in my
protected override void OnModelCreating(ModelBuilder modelBuilder)
method in ApplicationDbContext
.
...
public DbSet<State> States { get; set; }
public DbSet<LGA> LGAs { get; set; }
...
and I have a method Seed()
which is an extension method which I expect to run to seed the two tables.
I call the Seed()
method as follows:
modelBuilder.Seed();
The extension method is defined like this:
public static class ModelBuilderExtensions
{
public static void Seed(this ModelBuilder modelBuilder)
{
modelBuilder.Entity<State>().HasData(
new State { Id = 1, Name = "Abia" },
new State { Id = 2, Name = "Adamawa" },
new State { Id = 3, Name = "Akwa Ibom" },
new State { Id = 4, Name = "Anambra" },
new State { Id = 5, Name = "Bauchi" },
new State { Id = 6, Name = "Bayelsa" },
new State { Id = 7, Name = "Benue" },
new State { Id = 8, Name = "Borno" },
new State { Id = 9, Name = "Cross River" },
new State { Id = 10, Name = "Delta" },
new State { Id = 11, Name = "Ebonyi" },
new State { Id = 12, Name = "Edo" },
new State { Id = 13, Name = "Ekiti" },
new State { Id = 14, Name = "Enugu" },
new State { Id = 15, Name = "Gombe" },
new State { Id = 16, Name = "Imo" },
new State { Id = 17, Name = "Jigawa" },
new State { Id = 18, Name = "Kaduna" },
new State { Id = 19, Name = "Kano" },
new State { Id = 20, Name = "Katsina" },
new State { Id = 21, Name = "Kebbi" },
new State { Id = 22, Name = "Kogi" },
new State { Id = 23, Name = "Kwara" },
new State { Id = 24, Name = "Lagos" },
new State { Id = 25, Name = "Nasarawa" },
new State { Id = 26, Name = "Niger" },
new State { Id = 27, Name = "Ogun" },
new State { Id = 28, Name = "Ondo" },
new State { Id = 29, Name = "Osun" },
new State { Id = 30, Name = "Oyo" },
new State { Id = 31, Name = "Plateau" },
new State { Id = 32, Name = "Rivers" },
new State { Id = 33, Name = "Sokoto" },
new State { Id = 34, Name = "Taraba" },
new State { Id = 35, Name = "Yobe" },
new State { Id = 36, Name = "Zamfara" },
new State { Id = 37, Name = "Abuja (FCT)" },
new State { Id = 38, Name = "Non Nigerian" }
);
modelBuilder.Entity<LGA>().HasData(
new LGA { Id = 1, StateId = 1, Name = "Aba North" },
new LGA { Id = 2, StateId = 1, Name = "Aba South" },
new LGA { Id = 3, StateId = 1, Name = "Arochukwu" },
...
new LGA { Id = 784, StateId = 16, Name = "Ahiazu - Mbaise" },
new LGA { Id = 785, StateId = 38, Name = "Foreign" },
new LGA { Id = 786, StateId = 18, Name = "Kaduna South" },
new LGA { Id = 787, StateId = 16, Name = "Aboh - Mbaise" },
new LGA { Id = 788, StateId = 9, Name = "Odukpani" }
This is the relationship between the two entities
public class LGA
{
public int Id { get; set; }
[Display(Name="State")]
public int StateId { get; set; }
[Required]
public string Name { get; set; }
public ICollection<Town> Towns { get; set; }
[ForeignKey("StateId")]
public State State { get; set; }
public ICollection<ApplicationUser> Residents { get; set; }
}
public class State
{
public int Id { get; set; }
[Required]
public string Name { get; set; }
[Display(Name="State Code")]
public string Code { get; set; }
public ICollection<LGA> LGAs { get; set; }
public ICollection<ApplicationUser> Residents { get; set; }
}
But when I run update-database
, I get the following error:
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_LGAs_States_StateId". The conflict occurred in database...table "dbo.States", column 'Id'.
And I have made sure that all the states are included in the migration code.
However, I realize that when I check the States
table generated, I cannot seem to find that last row in the table, even though it is there in the data seeding code
I am running ASP.NET Core 2.2 with Entity Framework Core on a Windows 10 O.S.
Where could I be going wrong please?
Thank you for your assistance.
call seed function from startup.cs. Create Configuration class & inject it into Configure function of startup class. This is the another workaround for seeding data..`
public class Startup
{
public void Configure(Configurations dbMigrationsConfig)
{
try
{
dbMigrationsConfig.SeedData().Wait();
}
catch (Exception ex)
{
throw ex.InnerException;
}
}
}
public class Configurations
{
private readonly TemplateContext dbContext;
public Configurations(TemplateContext _dbContext)
{
dbContext = _dbContext;
}
public async Task SeedData()
{
//You seeding code
}
}`