Cannot use table 'AspNetUsers' in schema '' for entity 'AspNetUsers' since it is being used for another entity

Question

We are trying to add Identity 3 to our existing Customers app by extending AspNetUsers

    public class ApplicationUser : IdentityUser
{
    public string Busine         


        

Answer 1

As you inherit from IdentityDbContext, you don't need to recreate AspNet* DbSet, just add your new table.
Your CustomersContext should look like that:

public partial class CustomersContext : IdentityDbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder options)
    {
        options.UseSqlServer(@"Server=(localdb)\\mssqllocaldb;Database=Customers;Trusted_Connection=True;MultipleActiveResultSets=true");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);// we have to do this because we are inheriting from IdentityDbContext not DbContext

        // override the users tables with your properties
        modelBuilder.Entity(entity =>
        {
            entity.HasIndex(e => e.BusinessName).HasName("BusinessNameIndex");

            entity.HasIndex(e => e.NormalizedEmail).HasName("EmailIndex");

            entity.HasIndex(e => e.NormalizedUserName).HasName("UserNameIndex");

            entity.Property(e => e.Id).HasMaxLength(450);

            entity.Property(e => e.AddressLabel)
                .HasMaxLength(255)
                .HasColumnType("varchar");

            entity.Property(e => e.BusinessName)
                .HasMaxLength(255)
                .HasColumnType("varchar");

            entity.Property(e => e.ContactName)
                .HasMaxLength(255)
                .HasColumnType("varchar");

            entity.Property(e => e.CountryCode)
                .IsRequired()
                .HasMaxLength(2)
                .HasColumnType("varchar")
                .HasDefaultValue("00");

            entity.Property(e => e.FollowUp).HasColumnType("date");

            entity.Property(e => e.MailingList).HasDefaultValue(true);

            entity.HasOne(d => d.Country).WithMany(p => p.Users).HasForeignKey(d => d.CountryCode).OnDelete(DeleteBehavior.Restrict);

            entity.HasOne(d => d.Subscription).WithMany(p => p.Users).HasForeignKey(d => d.SubscriptionId).OnDelete(DeleteBehavior.Restrict);
        });

        modelBuilder.Entity(entity =>
        {
            entity.HasKey(e => e.CountryCode);

            entity.Property(e => e.CountryCode)
                .HasMaxLength(2)
                .HasColumnType("varchar");

            entity.Property(e => e.CalCost).HasColumnType("decimal");

            entity.Property(e => e.CountryName)
                .IsRequired()
                .HasMaxLength(50)
                .HasColumnType("varchar");

            entity.Property(e => e.CultureCode)
                .IsRequired()
                .HasMaxLength(8)
                .HasColumnType("varchar");

            entity.Property(e => e.CurrencyCode)
                .IsRequired()
                .HasMaxLength(3)
                .HasColumnType("varchar");

            entity.Property(e => e.InvoiceFooter)
                .HasMaxLength(50)
                .HasColumnType("varchar");

            entity.Property(e => e.InvoiceName)
                .IsRequired()
                .HasMaxLength(50)
                .HasColumnType("varchar");

            entity.Property(e => e.TaxName)
                .HasMaxLength(3)
                .HasColumnType("varchar");

            entity.Property(e => e.TaxRate).HasColumnType("decimal");
        });

        modelBuilder.Entity(entity =>
        {
            entity.HasKey(e => e.DeviceID);

            entity.Property(e => e.CALs).HasDefaultValue(0);

            entity.Property(e => e.DeviceName)
                .IsRequired()
                .HasMaxLength(50)
                .HasColumnType("varchar");

            entity.Property(e => e.UnlockedFrom).HasColumnType("date");

            entity.Property(e => e.UnlockedTo).HasColumnType("date");

            entity.Property(e => e.UserId)
                .IsRequired()
                .HasMaxLength(450);

            entity.HasOne(d => d.User).WithMany(p => p.Devices).HasForeignKey(d => d.UserId).OnDelete(DeleteBehavior.Restrict);
        });

        modelBuilder.Entity(entity =>
        {
            entity.HasKey(e => e.DownloadId);

            entity.Property(e => e.DownloadDate).HasColumnType("date");

            entity.Property(e => e.DownloadVersion)
                .IsRequired()
                .HasMaxLength(50)
                .HasColumnType("varchar");

            entity.Property(e => e.UserId)
                .IsRequired()
                .HasMaxLength(450);

            entity.HasOne(d => d.User).WithMany(p => p.Downloads).HasForeignKey(d => d.UserId).OnDelete(DeleteBehavior.Restrict);
        });

        modelBuilder.Entity(entity =>
        {
            entity.HasKey(e => e.InvoiceNr);

            entity.Property(e => e.AddressLabel)
                .IsRequired()
                .HasMaxLength(255)
                .HasColumnType("varchar");

            entity.Property(e => e.InvoiceDate).HasColumnType("date");

            entity.Property(e => e.InvoiceDescription)
                .IsRequired()
                .HasMaxLength(255)
                .HasColumnType("varchar");

            entity.Property(e => e.InvoiceNet).HasColumnType("money");

            entity.Property(e => e.InvoiceTax).HasColumnType("money");

            entity.Property(e => e.InvoiceTotal).HasColumnType("money");

            entity.Property(e => e.UserId)
                .IsRequired()
                .HasMaxLength(450);

            entity.HasOne(d => d.User).WithMany(p => p.Invoices).HasForeignKey(d => d.UserId).OnDelete(DeleteBehavior.Restrict);
        });

        modelBuilder.Entity(entity =>
        {
            entity.HasKey(e => e.NoteId);

            entity.Property(e => e.NoteDate).HasColumnType("date");

            entity.Property(e => e.NoteSubject)
                .IsRequired()
                .HasMaxLength(50)
                .HasColumnType("varchar");

            entity.Property(e => e.NoteText)
                .IsRequired()
                .HasColumnType("varchar");

            entity.Property(e => e.UserId)
                .IsRequired()
                .HasMaxLength(450);

            entity.HasOne(d => d.User).WithMany(p => p.Notes).HasForeignKey(d => d.UserId).OnDelete(DeleteBehavior.Restrict);
        });

        modelBuilder.Entity(entity =>
        {
            entity.HasKey(e => e.ReferralSourceId);

            entity.Property(e => e.ReferralSourceName)
                .IsRequired()
                .HasMaxLength(50)
                .HasColumnType("varchar");
        });

        modelBuilder.Entity(entity =>
        {
            entity.HasKey(e => e.ReferralId);

            entity.Property(e => e.ReferralDate).HasColumnType("date");

            entity.Property(e => e.UserId)
                .IsRequired()
                .HasMaxLength(450);

            entity.HasOne(d => d.ReferralSource).WithMany(p => p.Referrals).HasForeignKey(d => d.ReferralSourceID).OnDelete(DeleteBehavior.Restrict);

            entity.HasOne(d => d.User).WithMany(p => p.Referrals).HasForeignKey(d => d.UserId).OnDelete(DeleteBehavior.Restrict);
        });

        modelBuilder.Entity(entity =>
        {
            entity.HasKey(e => e.SubscriptionId);

            entity.Property(e => e.SubscriberId)
                .IsRequired()
                .HasMaxLength(450);

            entity.Property(e => e.SubscriptionExpires).HasColumnType("date");
            entity.Property(e => e.TotalCALs).HasDefaultValue(0);

        });
    }

    public virtual DbSet Countries { get; set; }
    public virtual DbSet Devices { get; set; }
    public virtual DbSet Downloads { get; set; }
    public virtual DbSet Invoices { get; set; }
    public virtual DbSet Notes { get; set; }
    public virtual DbSet ReferralSources { get; set; }
    public virtual DbSet Referrals { get; set; }
    public virtual DbSet Subscriptions { get; set; }
}

Or you can completely create the model without calling base.OnModelCreating, you can copy the OnModelCreating from the source code