Build a Simple Employee Management System with MongoDB and Flask

To reinforce MongoDB insert, delete, update, and query functions, this guide builds a simple employee management system project.

1 Understand Project Goal

The final result is a web page; you only need to develop the MongoDB‑related code.

The page displays personnel information with an “Add Person” button, allowing you to view, add, edit, and delete records.

Adding Information

Click the “Add Person” button to open a dialog, fill in the fields, and the data is stored in MongoDB and shown on the page.

Editing Information

Click the “Edit” button next to a record, modify fields (except ID and age, which are derived from birthdate), then click “Update” to save.

Deleting Information

Click the “Delete” button next to a record to remove it; the automatically generated employee ID never changes after deletion.

2 Preparation

2.1 Clone Project

git clone https://github.com/sunsharing-note/MonogoDB.git

2.2 Project Structure

The project includes:

Pipfile and Pipfile.lock for environment management.

answer/DataBaseManager.py – reference implementation.

bin/generate_data.py – script to insert initial data.

main.py, static, templates, util – backend and frontend code (no need to modify).

2.3 Set Up Environment

Use Pipenv to create an isolated virtual environment and install dependencies. python3 -m pip install pipenv Enter the project folder and run: pipenv install Activate the environment:

pipenv shell

2.4 Run Project

Linux/macOS:

export FLASK_APP=main.py
flask run

Windows:

set FLASK_APP=main.py
flask run

Open http://127.0.0.1:5000 in a browser to see the page with three test records.

3 Development Process

3.1 Generate Initial Data

Run generate_data.py after starting MongoDB; it creates database chapter_4 and collection people_info with 19 initial documents.

3.2 Implement Query Function

Complete query_info() to return all documents where deleted equals 0, excluding _id:

def query_info(self):
    info_list = list(self.handler.find({'deleted': 0}, {'_id': 0}))
    return info_list

3.3 Implement Add Function

Logic: if the collection is empty, the new employee ID is 1; otherwise it is the current maximum ID plus 1, then insert the record.

def _query_last_id(self):
    last_info = self.handler.find({}, {'_id': 0, 'id': 1}).sort('id', -1).limit(1)
    return last_info[0]['id'] if last_info else 0

3.4 Implement Update Function

def update_info(self, people_id, para_dict):
    try:
        self.handler.update_one({'id': people_id}, {'$set': para_dict})
    except Exception as e:
        return False
    return True

3.5 Implement Delete (Soft Delete)

Soft delete is achieved by setting deleted to 1.

def del_info(self, people_id):
    return self.update_info(people_id, {'deleted': 1})

Conclusion

This project uses a Flask‑based employee management website to help readers practice fundamental MongoDB operations. By modifying DataBaseManager.py, users can see real‑time results and gain confidence in using Python for data insertion, querying, updating, and soft deletion in everyday work.