在EF Core中定义关系 [英] Define relationship in EF Core

问题描述

如何在此处使用EF Core定义关系?

How do I define the relationships here with EF Core?

我有一个 Employee 表，其中有多个 Job

I have an Employee table which has multiple Jobs

public class Employee
{
    public int EmployeeId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public List<HourlyRate> DefaultRate { get; set; }
    public string Note { get; set; }
    public bool Active { get; set; }
    public DateTime DateHired { get; set; }
    public List<PhoneNumber> PhoneNumbers { get; set; }
    public List<Address> Addresses { get; set; }
    public List<Job> Jobs { get; set; }
    public bool Deleted { get; set; }
}

Job 类具有一个 Employee 对象，可以导航回该员工，而 Job 具有多个Director，这些Director也是Employees

And the Job class has an Employee object to navigate back to the employee and the Job has multiple Directors which are also Employees

public class Job
{
    public int JobId { get; set; }
    public Employee Employee { get; set; }
    public JobType Type { get; set; }
    public Department Department { get; set; }
    public List<Employee> Directors { get; set; }
    public bool Active { get; set; }
    public decimal HourlyRate { get; set; }
    public string Note { get; set; }
    public bool Deduction { get; set; }
    public int? DeductionPercent { get; set; }
}

这是我的 DbContext :

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Employee>()
                .HasMany(employee => employee.Jobs)
                .WithOne(i => i.Employee);
}

最初，工作只有一个Director，一切都很好，但要求已更改为拥有多个Director，并从Job表中删除了Director列，并向Employee表中添加了一个 JobId 列但是问题是，如果我通过 job.Directors.Add(director)将该导演添加到第二份工作中，EF会覆盖该导演的工作ID，并且该导演将从上一个工作中删除

Initially the Job only had a single Director and everything was good but the requirement has changed to have multiple directors and ef removed the Director column from the Job table and added a JobId column to the Employee table but the problem is that if i add that director to a second job by job.Directors.Add(director) EF overrides the job id of the of the director and the director is being removed from the previous job

我正在使用EF Core 2.2

I am using EF Core 2.2

推荐答案

尝试使用此代码.由于您的员工可以拥有一个或多个工作，因此我添加了EmployeeJob表和多对多关系.我认为您只需要将IsDirector标志添加到Employee或更好的东西，例如EmployeeType:

Try to use this code. Since your employee can have one or many jobs I added the table EmployeeJob and many-to-many relations. I think you just need to add IsDirector flag to Employee or maybe better something like an EmployeeType:

public class Employee

    {
        public Employee()
    {
        EmployeeJobs = new HashSet<EmployeeJob>();
    }
    [Key]
   
   public int EmployeeId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    
    public string Note { get; set; }
    public bool Active { get; set; }
    public DateTime DateHired { get; set; }
    
    
    public bool Deleted { get; set; }
    [InverseProperty(nameof(EmployeeJob.Employee))]
    public virtual ICollection<EmployeeJob> EmployeeJobs { get; set; }
}


public class Job
{
    public Job()
    {
        EmployeeJobs = new HashSet<EmployeeJob>();
    }
    [Required]
    public int JobId { get; set; }

    public bool Active { get; set; }
    public decimal HourlyRate { get; set; }
    public string Note { get; set; }
    public bool Deduction { get; set; }
    public int? DeductionPercent { get; set; }
    
    [InverseProperty(nameof(EmployeeJob.Job))]
    public virtual ICollection<EmployeeJob> EmployeeJobs { get; set; }
}

public class EmployeeJob
{
    [Key]
    public int Id { get; set; }

    public int EmployeeId { get; set; }

    [ForeignKey(nameof(EmployeeId))]
    [InverseProperty(nameof(EmployeeJob.Employee.EmployeeJobs))]
    public virtual Employee Employee { get; set; }

    public int JobId { get; set; }

    [ForeignKey(nameof(JobId))]
    [InverseProperty(nameof(EmployeeJob.Employee.EmployeeJobs))]
    public virtual Job Job { get; set; }
}


public class EmployeeDbContext : DbContext
{
    public EmployeeDbContext()
    {
    }

    public EmployeeDbContext(DbContextOptions<EmployeeDbContext> options)
        : base(options)
    {
    }
    public DbSet<Employee> Employees { get; set; }
    public DbSet<Job> Jobs { get; set; }
    public DbSet<EmployeeJob> EmployeeJobs { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
optionsBuilder.UseSqlServer(@"Server=localhost;Database=Employee;Trusted_Connection=True;");
    }
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<EmployeeJob>(entity =>
        {
            entity.HasOne(d => d.Employee)
                .WithMany(p => p.EmployeeJobs)
                .HasForeignKey(d => d.EmployeeId)
                .OnDelete(DeleteBehavior.ClientSetNull)
                .HasConstraintName("FK_EmployeeJob_Employee");

            entity.HasOne(d => d.Job)
                .WithMany(p => p.EmployeeJobs)
                .HasForeignKey(d => d.JobId)
                .OnDelete(DeleteBehavior.ClientSetNull)
                .HasConstraintName("FK_EmployeeJob_Job");
        });

    }

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