# Entities and Doctrine

Chamilo 2.0 has 314 Doctrine entities across two bundles.

## Entity Organization

### CoreBundle Entities (213)

Platform-level entities:

| Category      | Examples                                                                   |
| ------------- | -------------------------------------------------------------------------- |
| **Users**     | `User`, `UserRelUser`, `AccessUrl`, `AccessUrlRelUser`                     |
| **Courses**   | `Course`, `CourseCategory`, `CourseRelUser`                                |
| **Sessions**  | `Session`, `SessionRelUser`, `SessionRelCourse`, `SessionRelCourseRelUser` |
| **Resources** | `ResourceNode`, `ResourceFile`, `ResourceLink`, `ResourceType`             |
| **Settings**  | `SettingsCurrent`, `SettingsOptions`                                       |
| **Messages**  | `Message`, `MessageRelUser`, `MessageAttachment`                           |
| **Tracking**  | `TrackELogin`, `TrackEOnline`, `TrackEDefault`                             |
| **Skills**    | `Skill`, `SkillRelUser`, `SkillRelProfile`                                 |
| **AI**        | `AiRequests`                                                               |
| **Plugins**   | `Plugin`, `PluginRepository`                                               |
| **Social**    | `UserGroup`, `UsergroupRelUser`                                            |
| **xAPI**      | `XApiObject`, `XApiResult`, `XApiActivityState`                            |

### CourseBundle Entities (101)

Course content entities — all prefixed with `C`:

| Category           | Examples                                                                             |
| ------------------ | ------------------------------------------------------------------------------------ |
| **Documents**      | `CDocument`                                                                          |
| **Exercises**      | `CQuiz`, `CQuizQuestion`, `CQuizAnswer`, `CQuizQuestionCategory`                     |
| **Learning paths** | `CLp`, `CLpItem`, `CLpView`, `CLpItemView`, `CLpCategory`                            |
| **Forums**         | `CForum`, `CForumCategory`, `CForumThread`, `CForumPost`                             |
| **Assignments**    | `CStudentPublication`, `CStudentPublicationAssignment`, `CStudentPublicationComment` |
| **Surveys**        | `CSurvey`, `CSurveyQuestion`, `CSurveyAnswer`, `CSurveyInvitation`                   |
| **Attendance**     | `CAttendance`, `CAttendanceCalendar`, `CAttendanceResult`                            |
| **Blogs**          | `CBlog`, `CBlogPost`, `CBlogComment`, `CBlogTask`                                    |
| **Other**          | `CCalendarEvent`, `CGlossary`, `CLink`, `CLinkCategory`, `CNotebook`, `CWiki`        |

## Naming Convention

* CoreBundle entities: standard PascalCase (e.g., `User`, `Course`, `Session`)
* CourseBundle entities: prefixed with `C` (e.g., `CDocument`, `CQuiz`, `CLp`)

This prefix distinguishes course-scoped content entities from platform-level entities.

## Key Relationships

### User ↔ Course

```
User --[CourseRelUser]--> Course
```

`CourseRelUser` stores the enrollment status (TEACHER = 1, STUDENT = 5).

### User ↔ Session ↔ Course

```
User --[SessionRelUser]--> Session --[SessionRelCourse]--> Course
User --[SessionRelCourseRelUser]--> (Session + Course)
```

### ResourceNode (Content Abstraction)

All course content entities connect to the resource system through `ResourceNode`:

```
CDocument --> ResourceNode --> ResourceFile
CQuiz ------> ResourceNode
CLp --------> ResourceNode
```

See [Resource System](https://docs.chamilo.org/2.x/developer-guide/developer-guide/backend/resource-system) for details.

## Doctrine Extensions

Chamilo uses Gedmo Doctrine Extensions (via `stof/doctrine-extensions-bundle`):

* **Tree** — Hierarchical data (ResourceNode uses materialized path)
* **Timestampable** — Automatic `createdAt`/`updatedAt` fields
* **Sluggable** — URL-friendly slugs
* **Sortable** — Orderable collections