使用C#将外键插入到表中

// 定义实体类
public class ParentEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class ChildEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int ParentId { get; set; }  // 外键
    public ParentEntity Parent { get; set; }  // 导航属性
}

// 创建数据库上下文类
public class MyDbContext : DbContext
{
    public DbSet<ParentEntity> Parents { get; set; }
    public DbSet<ChildEntity> Children { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("连接字符串");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<ChildEntity>()
            .HasOne(c => c.Parent)
            .WithMany(p => p.Children)
            .HasForeignKey(c => c.ParentId);
    }
}

// 插入数据
using (var context = new MyDbContext())
{
    var parent = new ParentEntity { Name = "Parent" };
    var child = new ChildEntity { Name = "Child", Parent = parent };

    context.Parents.Add(parent);
    context.Children.Add(child);
    context.SaveChanges();
}