如何使用 ef 对迁移构建强制执行 Restrict DeleteBehavior？

Posted 2023-04-13

【中文标题】如何使用 ef 对迁移构建强制执行 Restrict DeleteBehavior？

【英文标题】：How to enforce Restrict DeleteBehavior for migration build using ef?

【发布时间】：2018-07-26 22:18:16

【问题描述】：

我有一个相关的PatientRegistry 表，它有三个相关的表，它们具有one-to-many 关系Country、State 和City。在迁移期间，默认 DeleteBehavior 设置为 Cascade，这在 database Update 期间给我一个错误。如果我将其更改为Restrict，我可以正确地seed。我试图在构建期间强制执行Restrictbehavior，但在播种期间我不断收到此错误，

未处理的异常：System.InvalidOperationException：关联 实体类型“City”和“PatientRegistry”之间已被切断，但 此关系的外键不能设置为空。如果 应该删除依赖实体，然后设置要使用的关系 级联删除。

如何防止构建过程中的级联删除行为？

我贴的是相关代码，

[Table("PatientsRegistry")]
    public class PatientRegistry
       [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    [Display(Name = "Record Id")]
        public long RecordId  get; set; 
        [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
        [Display(Name = "Patient File Number")]
        public long PatientFileId  get; set; 
        public int CountryId  get; set; 
        public Country Country  get; set; 
        public int StateId  get; set; 
        public State State  get; set; 
        public int CityId  get; set; 
        public City City  get; set; 
        [Timestamp]
        public byte[] RowVersion  get; set; 
        public ICollection<PartnerRegistry> Partners  get; set; 
        public PatientRegistry()
        
            Partners = new Collection<PartnerRegistry>();
        

    

在我的OnModelCreating

        builder.Entity<ApplicationUser>()
                .HasOne(c => c.Country)
                .WithOne()
                .OnDelete(DeleteBehavior.Restrict);

        builder.Entity<ApplicationUser>()
                .HasOne(c => c.State)
                .WithOne()
                .OnDelete(DeleteBehavior.Restrict);

        builder.Entity<ApplicationUser>()
                .HasOne(c => c.City)
                .WithOne()
                .OnDelete(DeleteBehavior.Restrict);

我按如下方式播种，

  if (!context.PatientsRegistry.Any())
                    

                        context.PatientsRegistry.AddRange(
                             new PatientRegistry
                             
                                 PatientFileId = 1111,
                                 CountryId = context.Countries.Where(g => g.Name == "Jordan").SingleOrDefault().Id,
                                 StateId = context.States.Where(g => g.Name == "Amman").SingleOrDefault().Id,
                                 CityId = context.Cities.Where(g => g.Name == "Abu Nusair").SingleOrDefault().Id,
                             

                        );
                        context.SaveChanges();


                    

【问题讨论】：

为什么是WithOne()？

@IvanStoev，你说得对，我完全相反，，，，应该是WithMany()

【参考方案1】：

完全错过了，应该是WithMany()

        builder.Entity<ApplicationUser>()
                .HasOne(c => c.Country)
                .WithMany()
                .OnDelete(DeleteBehavior.Restrict);

        builder.Entity<ApplicationUser>()
                .HasOne(c => c.State)
                .WithMany()
                .OnDelete(DeleteBehavior.Restrict);

        builder.Entity<ApplicationUser>()
                .HasOne(c => c.City)
                .WithMany()
                .OnDelete(DeleteBehavior.Restrict);