业务增长后文档管理系统迭代：新增部门 / 业务线时规则调整方法（附案例）

// 部门实体模型
public class Department
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Code { get; set; } // 部门编码
    public int? ParentDepartmentId { get; set; } // 上级部门ID
    public virtual Department ParentDepartment { get; set; }
    public virtual ICollection ChildDepartments { get; set; }
    public virtual ICollection DocumentPermissions { get; set; }
}

// 文档权限实体模型
public class DocumentPermission
{
    public int Id { get; set; }
    public int DocumentId { get; set; }
    public int DepartmentId { get; set; }
    public PermissionLevel PermissionLevel { get; set; } // 权限级别枚举
    public virtual Document Document { get; set; }
    public virtual Department Department { get; set; }
}

// 权限级别枚举定义
public enum PermissionLevel
{
    NoAccess = 0,
    ReadOnly = 1,
    ReadWrite = 2,
    FullControl = 3
}

// DbContext中配置关系
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    // 配置部门自引用关系
    modelBuilder.Entity()
        .HasOne(d => d.ParentDepartment)
        .WithMany(d => d.ChildDepartments)
        .HasForeignKey(d => d.ParentDepartmentId)
        .OnDelete(DeleteBehavior.Restrict);
    
    // 配置文档权限与部门的关系
    modelBuilder.Entity()
        .HasOne(dp => dp.Department)
        .WithMany(d => d.DocumentPermissions)
        .HasForeignKey(dp => dp.DepartmentId);
}