# dbNPCHandler Documentation

## Overview
This document describes the database relationships and interactions for the `dbNPCHandler` class. This handler manages non-player character (NPC) data, including their base properties, current state, and behaviors in the game world.

## Handler Class
**File:** `src/engine/db/handlers/dbNPCHandler.java`
**Class:** `dbNPCHandler`
**Extends:** `dbHandlerBase`

## Database Tables

### Main NPC Table
- **Table Name:** `dyn_npc`
- **Description:** Stores current state information for NPCs, including location, health, and behavior flags
- **Columns:** 
  - UID (Primary Key)
  - npcBaseID
  - zoneUUID
  - x
  - y
  - z
  - health
  - isAlive
  - behavior

### Related Tables

| Table Name | Description | Relationship |
|------------|-------------|--------------|
| `static_npc_base` | Base properties of NPCs | npcBaseID → static_npc_base.UID |

## Key Queries

### Get NPC by UID
```sql
SELECT * FROM dyn_npc WHERE `UID` = ?
```
**File:** `dbNPCHandler.java`, Line ~25

### Save NPC
```sql
INSERT INTO `dyn_npc` (`npcBaseID`, `zoneUUID`, `x`, `y`, `z`, `health`, `isAlive`, `behavior`) VALUES(?,?,?,?,?,?,?,?)
```
**File:** `dbNPCHandler.java`, Line ~40

### Get NPCs by Zone
```sql
SELECT * FROM dyn_npc WHERE `zoneUUID` = ?
```
**File:** `dbNPCHandler.java`, Line ~55

## Relationships

1. **NPC to NPC Base:** Many-to-one relationship via npcBaseID field referencing static_npc_base.UID
2. **NPC to Zone:** Many-to-one relationship via zoneUUID field referencing obj_zone.UID

## Java Field to Database Column Mappings

| Java Field | Database Column | Notes |
|------------|-----------------|-------|
| `UID` | `dyn_npc.UID` | Unique identifier for the NPC |
| `npcBaseID` | `dyn_npc.npcBaseID` | UID of the base NPC definition |
| `zoneUUID` | `dyn_npc.zoneUUID` | Zone where the NPC is located |
| `x` | `dyn_npc.x` | X coordinate of NPC position |
| `y` | `dyn_npc.y` | Y coordinate of NPC position |
| `z` | `dyn_npc.z` | Z coordinate of NPC position |
| `health` | `dyn_npc.health` | Current health of the NPC |
| `isAlive` | `dyn_npc.isAlive` | Flag indicating if NPC is alive |
| `behavior` | `dyn_npc.behavior` | Behavior type or state of the NPC |
| `other fields...` | Various columns | Other properties related to NPC state |