Updating the database using migration ASP.NET Core 3.1 MVC

Question

I work with ASP.NET Core 3.1 MVC and use SQL Server as database. When I update old models and add new models, I want to update the database. For this I use migration and the command

Add-Migration NameMigration

Next, I enter the Update-Database command, but I keep getting the following error:

Build started...
Build succeeded.

fail: Microsoft.EntityFrameworkCore.Database.Command[20102]
Failed executing DbCommand (99ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
CREATE TABLE [AspNetRoles] (
[Id] nvarchar(450) NOT NULL,
[Name] nvarchar(256) NULL,
[NormalizedName] nvarchar(256) NULL,
[ConcurrencyStamp] nvarchar(max) NULL,
CONSTRAINT [PK_AspNetRoles] PRIMARY KEY ([Id])
);

Failed executing DbCommand (99ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] CREATE TABLE [AspNetRoles] ( [Id] nvarchar(450) NOT NULL, [Name] nvarchar(256) NULL, [NormalizedName] nvarchar(256) NULL, [ConcurrencyStamp] nvarchar(max) NULL, CONSTRAINT [PK_AspNetRoles] PRIMARY KEY ([Id]) ); Microsoft.Data.SqlClient.SqlException (0x80131904): There is already an object named 'AspNetRoles' in the database. at Microsoft.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action1 wrapCloseInAction) at Microsoft.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action1 wrapCloseInAction) at Microsoft.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) at Microsoft.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady) at Microsoft.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean isAsync, Int32 timeout, Boolean asyncWrite) at Microsoft.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource1 completion, Boolean sendToPipe, Int32 timeout, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry, String methodName) at Microsoft.Data.SqlClient.SqlCommand.ExecuteNonQuery() at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteNonQuery(RelationalCommandParameterObject parameterObject) at Microsoft.EntityFrameworkCore.Migrations.MigrationCommand.ExecuteNonQuery(IRelationalConnection connection, IReadOnlyDictionary2 parameterValues) at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationCommandExecutor.ExecuteNonQuery(IEnumerable`1 migrationCommands, IRelationalConnection connection) at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration) at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.UpdateDatabase(String targetMigration, String contextType) at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabaseImpl(String targetMigration, String contextType) at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabase.<>c__DisplayClass0_0.<.ctor>b__0() at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)

ClientConnectionId:e6b96a6c-817f-4d97-9fac-d1deefdfde2c
Error Number:2714,State:6,Class:16
There is already an object named 'AspNetRoles' in the database.

Here is the Program file

public class Program
{
    public static async Task Main(string[] args)
    {
        var host = CreateHostBuilder(args).Build();

        using (var scope = host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;

            try
            {
                var db = scope.ServiceProvider.GetRequiredService<ApplicationContext>();
                db.Database.Migrate();

                var userManager = services.GetRequiredService<UserManager<User>>();
                var rolesManager = services.GetRequiredService<RoleManager<IdentityRole>>();
                await RoleInitializer.InitializeAsync(userManager, rolesManager);
                
                var context = services.GetRequiredService<ApplicationContext>();
                await BasicInformationInitialize.InitializeLCAsync(context);
            }
            catch (Exception ex)
            {
                var logger = services.GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, "An error occurred while seeding the database.");
            }
        }

        host.Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

and Context file.

public class ApplicationContext : IdentityDbContext<User>
{
    //code
    public DbSet<Model> TabelName { get; set; }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);
        //code
    }

    public ApplicationContext(DbContextOptions<ApplicationContext> options) : base(options)
    {
        Database.EnsureCreated();
    }

    
}

That is, I cannot update my database to the latest migration. How can you solve my problem?

Answer 1

I thank you very much #Jason Pan ! The issue is resolved. The following code was written in the "ApplicationContext" file:

public ApplicationContext(DbContextOptions<ApplicationContext> options) : base(options)
    {
        if(Database == null)
            Database.EnsureCreated();
    }