Module Update

docs/db/seed-data.md

@@ -0,0 +1,75 @@
+# Database Seeding Strategy
+
+**Status**: Implemented  
+**Script Location**: [`scripts/seed.ts`](../../scripts/seed.ts)  
+**Command**: `npm run db:seed`
+
+---
+
+## 1. Overview
+The seed script is designed to populate the database with a **representative set of data** that covers all core business scenarios. It serves two purposes:
+1.  **Development**: Provides a consistent baseline for developers.
+2.  **Validation**: Verifies complex schema relationships (e.g., recursive trees, JSON structures).
+
+## 2. Seed Data Topology
+
+### 2.1 Identity & Access Management (IAM)
+We strictly follow the RBAC model defined in `docs/architecture/001_database_schema_design.md`.
+
+*   **Roles**:
+    *   `admin`: System Administrator.
+    *   `teacher`: Academic Instructor.
+    *   `student`: Learner.
+    *   `grade_head`: Head of Grade Year (Demonstrates multi-role capability).
+*   **Users**:
+    *   `admin@next-edu.com` (Role: Admin)
+    *   `math@next-edu.com` (Role: Teacher + Grade Head)
+    *   `alice@next-edu.com` (Role: Student)
+
+### 2.2 Knowledge Graph
+Generates a hierarchical structure to test recursive queries (`parentId`).
+*   **Math** (Level 0)
+    *   └── **Algebra** (Level 1)
+        *   └── **Linear Equations** (Level 2)
+
+### 2.3 Question Bank
+Includes rich content and nested structures.
+1.  **Simple Single Choice**: "What is 2 + 2?"
+2.  **Composite Question (Reading Comprehension)**:
+    *   **Parent**: A reading passage.
+    *   **Child 1**: Single Choice question about the passage.
+    *   **Child 2**: Open-ended text question.
+
+### 2.4 Exams
+Demonstrates the new **JSON Structure** field (`exams.structure`).
+*   **Title**: "Algebra Mid-Term 2025"
+*   **Structure**:
+    ```json
+    [
+      {
+        "type": "group",
+        "title": "Part 1: Basics",
+        "children": [{ "type": "question", "questionId": "...", "score": 10 }]
+      },
+      {
+        "type": "group",
+        "title": "Part 2: Reading",
+        "children": [{ "type": "question", "questionId": "...", "score": 20 }]
+      }
+    ]
+    ```
+
+## 3. How to Run
+
+### Prerequisites
+Ensure your `.env` file contains a valid `DATABASE_URL`.
+
+### Execution
+Run the following command in the project root:
+
+```bash
+npm run db:seed
+```
+
+### Reset Behavior
+**WARNING**: The script currently performs a **TRUNCATE** on all core tables before seeding. This ensures a clean state but will **WIPE EXISTING DATA**.