c# - EF Core - 可能导致循环或多个级联路径

Question

我已经设置了我认为非常简单的数据库。但是我收到以下错误。

Introducing FOREIGN KEY constraint 'FK_User_Suburb_SuburbId' on table 'User' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint or index. See previous errors.

这是我的 CATALOGCONtext:

using JobsLedger.CATALOG.Entities;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Internal;

namespace JobsLedger.CATALOG
{
    public class CATALOGContext : DbContext
    {
        public DbSet<Tenant> Tenants { get; set; }
        public DbSet<User> Users { get; set; }
        public DbSet<Role> Roles { get; set; }
        public DbSet<State> States { get; set; }
        public DbSet<Suburb> Suburbs { get; set; }
        public DbSet<CATALOGCounter> Counters { get; set; }


        public CATALOGContext(DbContextOptions options) : base(options) { }



        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            foreach (var entity in modelBuilder.Model.GetEntityTypes())
            {
                entity.Relational().TableName = entity.DisplayName();
            }

            // User
            modelBuilder.Entity<User>().Property(u => u.UserName).IsRequired().HasMaxLength(50);
            modelBuilder.Entity<User>().Property(u => u.UserFirstName).IsRequired().HasMaxLength(100);
            modelBuilder.Entity<User>().Property(u => u.UserLastName).IsRequired().HasMaxLength(100);
            modelBuilder.Entity<User>().Property(u => u.Email).IsRequired().HasMaxLength(200);
            modelBuilder.Entity<User>().Property(u => u.HashedPassword).IsRequired().HasMaxLength(200);
            modelBuilder.Entity<User>().Property(u => u.Salt).IsRequired().HasMaxLength(200);

            modelBuilder.Entity<User>()
                .HasOne<Suburb>(s => s.Suburb)
                .WithMany(u => u.Users)
                .HasForeignKey(u => u.SuburbId)
                .IsRequired(false);

            // Role
            modelBuilder.Entity<Role>().Property(r => r.Name).IsRequired().HasMaxLength(50);

            modelBuilder.Entity<Role>()
                .HasOne<User>(u => u.User)
                .WithOne(r => r.Role)
                .HasForeignKey<User>(u => u.RoleId);

            // TenantAccount
            modelBuilder.Entity<Tenant>().Property(t => t.TenantNo).HasMaxLength(20);
            modelBuilder.Entity<Tenant>().Property(t => t.Company).HasMaxLength(100).IsRequired();
            modelBuilder.Entity<Tenant>().Property(t => t.ContactLastName).HasDefaultValue(false).IsRequired();
            modelBuilder.Entity<Tenant>().Property(t => t.Email).HasMaxLength(500).IsRequired();
            modelBuilder.Entity<Tenant>().Property(t => t.MobilePhone).HasMaxLength(20).IsRequired();
            modelBuilder.Entity<Tenant>().Property(t => t.OfficePhone).HasMaxLength(20);
            modelBuilder.Entity<Tenant>().Property(t => t.CompanyEmail).HasMaxLength(500);
            modelBuilder.Entity<Tenant>().Property(t => t.Address1).HasMaxLength(500);
            modelBuilder.Entity<Tenant>().Property(t => t.Address2).HasMaxLength(500);
            modelBuilder.Entity<Tenant>().Property(t => t.ABN).HasMaxLength(14);
            modelBuilder.Entity<Tenant>().Property(t => t.Database).HasMaxLength(100).IsRequired();
            modelBuilder.Entity<Tenant>().Property(t => t.IsLocked).HasDefaultValue(false);

            modelBuilder.Entity<Tenant>()
                .HasOne<User>(s => s.User)
                .WithMany(ta => ta.Tenants)
                .HasForeignKey(u => u.UserId);

            modelBuilder.Entity<Tenant>()
                .HasOne(s => s.Suburb)
                .WithMany(ta => ta.Tenants)
                .HasForeignKey(ta => ta.SuburbId);

            // State
            modelBuilder.Entity<State>().Property(s => s.StateShortName).HasMaxLength(3).IsRequired();
            modelBuilder.Entity<State>().Property(s => s.StateName).HasMaxLength(30).IsRequired();

            // Suburb
            modelBuilder.Entity<Suburb>().Property(s => s.SuburbName).HasMaxLength(3).IsRequired();
            modelBuilder.Entity<Suburb>().Property(s => s.PostCode).HasMaxLength(30).IsRequired();

            modelBuilder.Entity<Suburb>()
                .HasOne<State>(s => s.State)
                .WithMany(su => su.Suburbs)
                .HasForeignKey(st => st.StateId);
        }
    }
}

这是我的用户:

...
        public int? SuburbId { get; set; }
        public Suburb Suburb { get; set; }

        public int RoleId { get; set; }
        public Role Role { get; set; }

        public virtual ICollection<Tenant> Tenants { get; set; }

这是我的郊区，也提到了..

想知道是否有人可能会强调迁移工作的原因，但是当我尝试启动数据库时，它会出现上述错误。

西蒙

Answer 1

该错误已经说明您需要做什么。指定执行操作时必须执行的操作。您应该添加 .OnDelete()每个外键定义的方法。

modelBuilder.Entity<Tenant>()
                .HasOne<User>(s => s.User)
                .WithMany(ta => ta.Tenants)
                .HasForeignKey(u => u.UserId)
                .OnDelete(DeleteBehavior.Restrict);

更多信息请阅读 https://www.learnentityframeworkcore.com/configuration/fluent-api/ondelete-method