# saurabh-bhargav/3-tier-nodejs-mysql-main architecture

> Architecture diagram of the GitHub repository saurabh-bhargav/3-tier-nodejs-mysql-main, generated by GitDiagram from its file tree, README and a sample of source files (last updated 2026-11-10). It is an AI-made overview: check details against the source.

- Interactive diagram: https://gitdiagram.com/saurabh-bhargav/3-tier-nodejs-mysql-main
- Repository: https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main

## Overview

This is a React/Express user-management app backed by MySQL. The intended workflow is to view users and add, edit, or delete them through a browser UI and API. The sampled code shows two overlapping implementations: App.js fetches and adds directly, while UsersList uses an API client and UserItem for deletion; the controller-based routes support listing, adding, and deleting. A separate server.js implements direct SQL routes, and server/routes/users.js contains update support. The README documents editing, but the sampled UI edit buttons are placeholders. These parallel paths are shown without assuming they are wired together.

Main entry points: [`client/src/App.js`](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/App.js) (Main app), [`client/src/components/UsersList.js`](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/components/UsersList.js) (Users list), [`server/server.js`](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/server.js) (Standalone server), [`server/config/db.js`](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/config/db.js) (DB connection)

## Diagram (Mermaid)

```mermaid
flowchart TD

subgraph group_client["Browser UI"]
  node_app_ui["Main app<br/>[App.js]"]
  node_app_styles["App styling<br/>[App.css]"]
  node_users_list["Users list<br/>[UsersList.js]"]
  node_user_item["User item<br/>[UserItem.js]"]
end

subgraph group_client_api["Client API"]
  node_api_client["User API client<br/>[users.js]"]
end

subgraph group_backend["Express backend"]
  node_express_app["Express app<br/>[app.js]"]
  node_user_routes["User routes<br/>[userRoutes.js]"]
  node_user_controller["User controller<br/>[userController.js]"]
  node_legacy_routes["Direct SQL routes<br/>[users.js]"]
  node_standalone_server["Standalone server<br/>[server.js]"]
end

subgraph group_data["Persistence"]
  node_user_model["User model<br/>[userModel.js]"]
  node_db_config["DB connection<br/>[db.js]"]
end

node_browser(("User"))
node_mysql[("MySQL")]

node_browser -->|"uses"| node_app_ui
node_app_ui -->|"imports"| node_app_styles
node_app_ui -->|"requests users"| node_standalone_server
node_browser -->|"views users"| node_users_list
node_users_list -->|"calls"| node_api_client
node_users_list -->|"renders"| node_user_item
node_api_client -->|"requests users"| node_standalone_server
node_express_app -->|"mounts"| node_user_routes
node_user_routes -->|"dispatches"| node_user_controller
node_user_controller -->|"calls"| node_user_model
node_user_model -->|"queries"| node_db_config
node_db_config -->|"connects"| node_mysql
node_legacy_routes -->|"queries"| node_db_config
node_standalone_server -->|"queries"| node_mysql

click node_app_ui "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/App.js"
click node_app_styles "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/App.css"
click node_users_list "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/components/UsersList.js"
click node_user_item "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/components/UserItem.js"
click node_api_client "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/api/users.js"
click node_express_app "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/app.js"
click node_user_routes "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/routes/userRoutes.js"
click node_user_controller "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/controllers/userController.js"
click node_user_model "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/models/userModel.js"
click node_db_config "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/config/db.js"
click node_legacy_routes "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/routes/users.js"
click node_standalone_server "https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/server.js"

classDef toneNeutral fill:#f8fafc,stroke:#334155,stroke-width:1.5px,color:#0f172a
classDef toneBlue fill:#dbeafe,stroke:#2563eb,stroke-width:1.5px,color:#172554
classDef toneAmber fill:#fef3c7,stroke:#d97706,stroke-width:1.5px,color:#78350f
classDef toneMint fill:#dcfce7,stroke:#16a34a,stroke-width:1.5px,color:#14532d
classDef toneRose fill:#ffe4e6,stroke:#e11d48,stroke-width:1.5px,color:#881337
classDef toneIndigo fill:#e0e7ff,stroke:#4f46e5,stroke-width:1.5px,color:#312e81
classDef toneTeal fill:#ccfbf1,stroke:#0f766e,stroke-width:1.5px,color:#134e4a
class node_app_ui,node_app_styles,node_users_list,node_user_item,node_browser toneBlue
class node_api_client,node_mysql toneAmber
class node_express_app,node_user_routes,node_user_controller,node_legacy_routes,node_standalone_server toneMint
class node_user_model,node_db_config toneRose
```

## Components

### Browser UI

- [Main app](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/App.js): `client/src/App.js`
- [App styling](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/App.css): `client/src/App.css`
- [Users list](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/components/UsersList.js): `client/src/components/UsersList.js`
- [User item](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/components/UserItem.js): `client/src/components/UserItem.js`

### Client API

- [User API client](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/client/src/api/users.js): `client/src/api/users.js`

### Express backend

- [Express app](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/app.js): `server/app.js`
- [User routes](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/routes/userRoutes.js): `server/routes/userRoutes.js`
- [User controller](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/controllers/userController.js): `server/controllers/userController.js`
- [Direct SQL routes](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/routes/users.js): `server/routes/users.js`
- [Standalone server](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/server.js): `server/server.js`

### Persistence

- [User model](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/models/userModel.js): `server/models/userModel.js`
- [DB connection](https://github.com/saurabh-bhargav/3-tier-nodejs-mysql-main/blob/main/server/config/db.js): `server/config/db.js`

### Other components

- **User**
- **MySQL**

## Connections

- User → Main app: uses (evidence: `README.md`)
- Main app → App styling: imports (evidence: `client/src/App.js`)
- Main app → Standalone server: requests users (evidence: `client/src/App.js`)
- User → Users list: views users (evidence: `README.md`)
- Users list → User API client: calls (evidence: `client/src/components/UsersList.js`)
- Users list → User item: renders (evidence: `client/src/components/UsersList.js`)
- User API client → Standalone server: requests users (evidence: `client/src/api/users.js`)
- Express app → User routes: mounts (evidence: `server/app.js`)
- User routes → User controller: dispatches (evidence: `server/routes/userRoutes.js`)
- User controller → User model: calls (evidence: `server/controllers/userController.js`)
- User model → DB connection: queries (evidence: `server/models/userModel.js`)
- DB connection → MySQL: connects (evidence: `server/config/db.js`)
- Direct SQL routes → DB connection: queries (evidence: `server/routes/users.js`)
- Standalone server → MySQL: queries (evidence: `server/server.js`)