User Management System - Class Diagram

This class diagram systematically represents the relationships between users, roles, and permissions in a user management system through object-oriented design, providing a foundational model for implementing flexible access control mechanisms.

Core Classes and Attributes

1. User
   • Attributes: User ID, Username, Password, Email, Creation Time
   • Associations:
     • Many-to-many relationship with Role (via the intermediate class UserRole), indicating a user can have multiple roles, and a role can be assigned to multiple users.
2. Role
   • Attributes: Role ID, Role Name (e.g., "Administrator", "Editor", "Regular User"), Description
   • Associations:
     • Many-to-many relationship with Permission (via the intermediate class RolePermission), indicating a role can have multiple permissions, and a permission can be allocated to multiple roles.
3. Permission
   • Attributes: Permission ID, Permission Name (e.g., "Create Article", "Delete User"), Permission Code (e.g., "ARTICLE_CREATE"), Description
   • Associations:
     • Many-to-one relationship with Resource, indicating permissions are tied to specific resources (e.g., "Articles", "Users").
4. Resource
   • Attributes: Resource ID, Resource Name (e.g., "Articles", "Comments"), Resource Path (e.g., "/api/articles")

Relationships and Intermediate Classes

1. UserRole (User-Role Association)
   • Attributes: Association ID, User ID, Role ID, Assignment Time
   • Purpose: Implements the many-to-many relationship between users and roles, recording role assignment details.
2. RolePermission (Role-Permission Association)
   • Attributes: Association ID, Role ID, Permission ID, Assignment Time
   • Purpose: Implements the many-to-many relationship between roles and permissions, recording permission allocation details.

Key Design Patterns and Principles

1. RBAC (Role-Based Access Control)
   • Uses Role as an intermediary layer to decouple users from permissions, simplifying permission management (e.g., bulk role assignments).
2. Fine-Grained Permission Control
   • The association between Permission and Resource supports granular control over different resources (e.g., API endpoints, page elements).
3. Extensible Design
   • Allows extension of the User class via inheritance (e.g., AdminUser, GuestUser) or introduces PermissionGroup for hierarchical permission organization.

Application Scenarios

• System Login and Authorization: Verifies user roles and permissions to control page access and functional operations.
• Permission Auditing: Traces permission change history through records in UserRole and RolePermission.
• Dynamic Permission Adjustment: Enables runtime modification of role permissions without system restart.

Visualization Key Points in the Class Diagram

• Inheritance: Represented by hollow triangular arrows (e.g., AdminUser extends User if specialized user types exist).
• Associations:
  • User ←[Many-to-Many]→ Role: Linked via UserRole.
  • Role ←[Many-to-Many]→ Permission: Linked via RolePermission.
  • Permission →[Many-to-One]→ Resource: Permissions are scoped to specific resources.
• Attributes and Methods: Class attributes are explicitly listed, while methods can be simplified (e.g., authenticate(), checkPermission()).

Implementation Recommendations

• Database Mapping: Each class maps to a database table, with intermediate classes corresponding to join tables.
• Permission Validation Flow: After user login, the system loads their roles and permissions, validating permissions during resource requests.
• Caching Optimization: Caches user permissions (e.g., in Redis) to reduce database queries.

This model enables flexible configuration of user permissions, adapting to access control requirements in diverse business scenarios (e.g., enterprise management systems, e-commerce platforms).