# Location Management CRUD - Complete Implementation

## ✅ Database Tables (Ready)

All tables are created with proper Primary Keys and Foreign Keys:

### 1. **countries** Table
- Primary Key: `id` (AUTO_INCREMENT)
- Unique Constraint: `unique_country_name` on `name`
- Indexes: `code`, `is_active`
- Fields: `id`, `name`, `code`, `is_active`, `created_at`, `updated_at`

### 2. **divisions** Table
- Primary Key: `id` (AUTO_INCREMENT)
- Foreign Key: `country_id` → `countries(id)` (CASCADE DELETE/UPDATE)
- Unique Constraint: `unique_division_name_country` on (`country_id`, `name`)
- Indexes: `country_id`, `code`, `is_active`
- Fields: `id`, `country_id`, `name`, `code`, `is_active`, `created_at`, `updated_at`

### 3. **districts** Table
- Primary Key: `id` (AUTO_INCREMENT)
- Foreign Key: `division_id` → `divisions(id)` (CASCADE DELETE/UPDATE)
- Unique Constraint: `unique_district_name_division` on (`division_id`, `name`)
- Indexes: `division_id`, `code`, `is_active`
- Fields: `id`, `division_id`, `name`, `code`, `is_active`, `created_at`, `updated_at`

### 4. **thanas** Table
- Primary Key: `id` (AUTO_INCREMENT)
- Foreign Key: `district_id` → `districts(id)` (CASCADE DELETE/UPDATE)
- Unique Constraint: `unique_thana_name_district` on (`district_id`, `name`)
- Indexes: `district_id`, `code`, `is_active`
- Fields: `id`, `district_id`, `name`, `code`, `is_active`, `created_at`, `updated_at`

## ✅ Models (Complete)

All models have full CRUD operations:

### Country Model (`src/models/Country.js`)
- ✅ `create()` - Create new country
- ✅ `findById()` - Get country by ID
- ✅ `findAll()` - Get all countries with pagination
- ✅ `update()` - Update country
- ✅ `delete()` - Soft delete country
- ✅ `getStatistics()` - Get location statistics

### Division Model (`src/models/Division.js`)
- ✅ `create()` - Create new division
- ✅ `findById()` - Get division by ID
- ✅ `findAll()` - Get all divisions with pagination
- ✅ `findByCountryId()` - Get divisions by country (for cascading dropdowns)
- ✅ `update()` - Update division
- ✅ `delete()` - Soft delete division

### District Model (`src/models/District.js`)
- ✅ `create()` - Create new district
- ✅ `findById()` - Get district by ID
- ✅ `findAll()` - Get all districts with pagination
- ✅ `findByDivisionId()` - Get districts by division (for cascading dropdowns)
- ✅ `update()` - Update district
- ✅ `delete()` - Soft delete district

### Thana Model (`src/models/Thana.js`)
- ✅ `create()` - Create new thana
- ✅ `findById()` - Get thana by ID
- ✅ `findAll()` - Get all thanas with pagination
- ✅ `findByDistrictId()` - Get thanas by district (for cascading dropdowns)
- ✅ `update()` - Update thana
- ✅ `delete()` - Soft delete thana

## ✅ Controllers (Complete)

All CRUD operations implemented in `src/controllers/locationController.js`:

### Countries
- ✅ `getCountries()` - GET `/api/locations/countries` (with pagination)
- ✅ `getCountryById()` - GET `/api/locations/countries/:id`
- ✅ `createCountry()` - POST `/api/locations/countries`
- ✅ `updateCountry()` - PUT `/api/locations/countries/:id`
- ✅ `deleteCountry()` - DELETE `/api/locations/countries/:id`

### Divisions
- ✅ `getDivisions()` - GET `/api/locations/divisions` (with pagination)
- ✅ `getDivisionsByCountry()` - GET `/api/locations/divisions/country/:country_id` (cascading)
- ✅ `getDivisionById()` - GET `/api/locations/divisions/:id`
- ✅ `createDivision()` - POST `/api/locations/divisions`
- ✅ `updateDivision()` - PUT `/api/locations/divisions/:id`
- ✅ `deleteDivision()` - DELETE `/api/locations/divisions/:id`

### Districts
- ✅ `getDistricts()` - GET `/api/locations/districts` (with pagination)
- ✅ `getDistrictsByDivision()` - GET `/api/locations/districts/division/:division_id` (cascading)
- ✅ `getDistrictById()` - GET `/api/locations/districts/:id`
- ✅ `createDistrict()` - POST `/api/locations/districts`
- ✅ `updateDistrict()` - PUT `/api/locations/districts/:id`
- ✅ `deleteDistrict()` - DELETE `/api/locations/districts/:id`

### Thanas
- ✅ `getThanas()` - GET `/api/locations/thanas` (with pagination)
- ✅ `getThanasByDistrict()` - GET `/api/locations/thanas/district/:district_id` (cascading)
- ✅ `getThanaById()` - GET `/api/locations/thanas/:id`
- ✅ `createThana()` - POST `/api/locations/thanas`
- ✅ `updateThana()` - PUT `/api/locations/thanas/:id`
- ✅ `deleteThana()` - DELETE `/api/locations/thanas/:id`

## ✅ Routes (Complete)

All routes registered in `src/routes/locations.js`:
- ✅ Authentication middleware applied
- ✅ Validation middleware applied
- ✅ All CRUD endpoints configured
- ✅ Cascading dropdown endpoints configured

## ✅ Validation (Complete)

All validation rules in `src/middleware/locationValidation.js`:
- ✅ Country validation (name required, code optional)
- ✅ Division validation (country_id required, name required, code optional)
- ✅ District validation (division_id required, name required, code optional)
- ✅ Thana validation (district_id required, name required, code optional)

## 📋 API Endpoints Summary

### Countries
```
GET    /api/locations/countries              - List all countries (paginated)
GET    /api/locations/countries/:id          - Get country by ID
POST   /api/locations/countries              - Create country
PUT    /api/locations/countries/:id          - Update country
DELETE /api/locations/countries/:id         - Delete country (soft delete)
```

### Divisions
```
GET    /api/locations/divisions                      - List all divisions (paginated)
GET    /api/locations/divisions/country/:country_id  - Get divisions by country
GET    /api/locations/divisions/:id                  - Get division by ID
POST   /api/locations/divisions                     - Create division
PUT    /api/locations/divisions/:id                 - Update division
DELETE /api/locations/divisions/:id                 - Delete division (soft delete)
```

### Districts
```
GET    /api/locations/districts                      - List all districts (paginated)
GET    /api/locations/districts/division/:division_id - Get districts by division
GET    /api/locations/districts/:id                  - Get district by ID
POST   /api/locations/districts                     - Create district
PUT    /api/locations/districts/:id                 - Update district
DELETE /api/locations/districts/:id                 - Delete district (soft delete)
```

### Thanas
```
GET    /api/locations/thanas                      - List all thanas (paginated)
GET    /api/locations/thanas/district/:district_id - Get thanas by district
GET    /api/locations/thanas/:id                  - Get thana by ID
POST   /api/locations/thanas                      - Create thana
PUT    /api/locations/thanas/:id                  - Update thana
DELETE /api/locations/thanas/:id                 - Delete thana (soft delete)
```

## 🔧 Features

1. **Soft Delete**: All delete operations use soft delete (sets `is_active = 0`)
2. **Cascade Delete**: Database foreign keys configured with CASCADE DELETE
3. **Pagination**: All list endpoints support pagination with `page` and `limit` query params
4. **Search**: All list endpoints support search with `search` query param
5. **Filtering**: Divisions, Districts, and Thanas can be filtered by parent ID
6. **Cascading Dropdowns**: Special endpoints for getting child records by parent ID
7. **Validation**: All create/update operations are validated
8. **Authentication**: All endpoints require authentication token

## 📝 Example API Calls

### Create Country
```bash
POST /api/locations/countries
Headers: { "Authorization": "Bearer <token>" }
Body: {
  "name": "Bangladesh",
  "code": "BD"
}
```

### Get Divisions by Country
```bash
GET /api/locations/divisions/country/1
Headers: { "Authorization": "Bearer <token>" }
```

### Create Division
```bash
POST /api/locations/divisions
Headers: { "Authorization": "Bearer <token>" }
Body: {
  "country_id": 1,
  "name": "Dhaka",
  "code": "DHK"
}
```

### Get Districts by Division
```bash
GET /api/locations/districts/division/1
Headers: { "Authorization": "Bearer <token>" }
```

### Create District
```bash
POST /api/locations/districts
Headers: { "Authorization": "Bearer <token>" }
Body: {
  "division_id": 1,
  "name": "Dhaka",
  "code": "DHK"
}
```

### Get Thanas by District
```bash
GET /api/locations/thanas/district/1
Headers: { "Authorization": "Bearer <token>" }
```

### Create Thana
```bash
POST /api/locations/thanas
Headers: { "Authorization": "Bearer <token>" }
Body: {
  "district_id": 1,
  "name": "Dhanmondi",
  "code": "DHN"
}
```

## ✅ Status: READY FOR USE

All database tables, models, controllers, routes, and validations are complete and ready for use. The system supports full CRUD operations with proper foreign key relationships and cascading functionality.