# System Architecture

## Overview

The Site-19 Database System is a relational data model designed to represent a structured containment facility.

It separates system responsibilities into distinct layers to ensure scalability, maintainability and clear separation between static data and dynamic operational logic.

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## Core Entities

The system revolves around the following entities:

- Personnel: staff members with hierarchical clearance levels
- D-Class personnel: expirable staff members used in experiments
- SCP: anomalous objects classified by containment risk (Safe, Euclid, Keter)
- Locations: physical containment zones within the facility (SZ - Surface Zone, EZ - Entrance Zone, LCZ - Light Containment Zone, HCZ - Heavy Containment Zone)
- States: runtime status tracking for both personnel and SCPs
- Experiments: actions conducted by personnel on SCPs, in goal of leaning more about said SCPs
- Tasks: shows availability of personnel and SCPs

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## Access Control Model

System access is governed by a clearance based model:

- Clearance determines visibility and interaction rights
- Higher clearance levels inherit lower-level permissions
- SCP data access is separated from physical containment access

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### Location System

Facility space is divided into hierarchical operational zones:

- SZ (Surface Zone): External facility infrastructure.
- EZ (Entrance Zone): Controlled transition area between the surface and containment facility. Used for general staff accommodation.
- LCZ (Light Containment Zone): Area designated for low-risk or safely contained SCPs. Also serves as accommodation for D-Class personnel.
- HCZ (High Containment Zone): Area designated for high-risk or unstable SCPs.

Each SCP is assigned to a location based on classification level, containment requirements, and operational constraints within the facility structure.

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## Architecture Layers

The system is divided into three primary layers:

### 1. Static Data Layer
Represents core static entities:
- Personnel records
- SCP records
- Facility locations
- Containment definitions
- Experiments records

This layer defines "what exists".

### 2. State Layer
Represents dynamic runtime conditions of the system:
- Personnel state (idle, assigned, on_task, unknown)
- SCP status (contained, breached, unknown)
- Location state (normal, locked_down, maintance, compromised)

This layer defines "what is happening".

### 3. Application Layer
Handles all external operations interacting with the database:
- Task assignment
- Logging
- User interaction via web interface

This layer defines "how it works together used".

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## Summary

This architecture models a structured containment facility as a relational system with strict separation between static entities, dynamic state and operational logic.

The design allows scalable expansion of personnel, SCPs and operational scenarios without requiring fundamental schema redesign.