#PyQt5 #SQLite #DesktopApp #Pharmacy #Barcode #Python

Lesson: Building a Pharmacy Management System with PyQt5 and Barcode Scanning

This tutorial will guide you through creating a complete desktop application for managing a pharmacy. The system will use a SQLite database for inventory, and a Point of Sale (POS) interface that uses barcode scanning to add drugs to a sale and automatically deducts stock upon completion.

---

#Step 1: Database Setup (database.py)

First, we create a dedicated file to handle all SQLite database operations. This keeps our data logic separate from our UI logic. Create a file named database.py.

import sqlite3

DB_NAME = 'pharmacy.db'

def connect():
    return sqlite3.connect(DB_NAME)

def setup_database():
    conn = connect()
    cursor = conn.cursor()
    cursor.execute('''
        CREATE TABLE IF NOT EXISTS drugs (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL,
            barcode TEXT NOT NULL UNIQUE,
            quantity INTEGER NOT NULL,
            price REAL NOT NULL,
            expiry_date TEXT NOT NULL
        )
    ''')
    conn.commit()
    conn.close()

def add_drug(name, barcode, quantity, price, expiry_date):
    conn = connect()
    cursor = conn.cursor()
    try:
        cursor.execute("INSERT INTO drugs (name, barcode, quantity, price, expiry_date) VALUES (?, ?, ?, ?, ?)",
                       (name, barcode, quantity, price, expiry_date))
        conn.commit()
    except sqlite3.IntegrityError:
        return False # Barcode already exists
    finally:
        conn.close()
    return True

def get_all_drugs():
    conn = connect()
    cursor = conn.cursor()
    cursor.execute("SELECT id, name, barcode, quantity, price, expiry_date FROM drugs ORDER BY name")
    drugs = cursor.fetchall()
    conn.close()
    return drugs

def find_drug_by_barcode(barcode):
    conn = connect()
    cursor = conn.cursor()
    cursor.execute("SELECT id, name, barcode, quantity, price, expiry_date FROM drugs WHERE barcode = ?", (barcode,))
    drug = cursor.fetchone()
    conn.close()
    return drug

def update_drug_quantity(drug_id, sold_quantity):
    conn = connect()
    cursor = conn.cursor()
    cursor.execute("UPDATE drugs SET quantity = quantity - ? WHERE id = ?", (sold_quantity, drug_id))
    conn.commit()
    conn.close()

# Hashtags: #SQLite #DatabaseDesign #DataPersistence #Python

---

#Step 2: Main Application and Inventory Management UI

Create the main application file, main.py. We will set up the main window with tabs for "Point of Sale" and "Inventory Management". We will fully implement the inventory tab first, allowing users to view and add drugs to the database.

import sys
from PyQt5.QtWidgets import *
from PyQt5.QtCore import QDate
import database as db

class PharmacyApp(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Pharmacy Management System")
        self.setGeometry(100, 100, 1200, 700)
        db.setup_database()

        self.tabs = QTabWidget()
        self.setCentralWidget(self.tabs)

        self.pos_tab = QWidget()
        self.inventory_tab = QWidget()

        self.tabs.addTab(self.pos_tab, "Point of Sale")
        self.tabs.addTab(self.inventory_tab, "Inventory Management")

        self.setup_inventory_ui()
        # self.setup_pos_ui() will be done in the next step

        self.load_inventory_data()

    def setup_inventory_ui(self):
        layout = QVBoxLayout()
        self.inventory_table = QTableWidget()
        self.inventory_table.setColumnCount(6)
        self.inventory_table.setHorizontalHeaderLabels(['ID', 'Name', 'Barcode', 'Quantity', 'Price', 'Expiry Date'])
        layout.addWidget(self.inventory_table)
        
        form = QFormLayout()
        self.drug_name = QLineEdit()
        self.drug_barcode = QLineEdit()
        self.drug_qty = QSpinBox()
        self.drug_qty.setRange(0, 9999)
        self.drug_price = QLineEdit()
        self.drug_expiry = QDateEdit(QDate.currentDate().addYears(1))
        self.drug_expiry.setDisplayFormat("yyyy-MM-dd")
        
        form.addRow("Name:", self.drug_name)
        form.addRow("Barcode:", self.drug_barcode)
        form.addRow("Quantity:", self.drug_qty)
        form.addRow("Price:", self.drug_price)
        form.addRow("Expiry Date:", self.drug_expiry)
        add_btn = QPushButton("Add Drug to Inventory")
        add_btn.clicked.connect(self.add_drug_to_db)
        
        layout.addLayout(form)
        layout.addWidget(add_btn)
        self.inventory_tab.setLayout(layout)

    def load_inventory_data(self):
        drugs = db.get_all_drugs()
        self.inventory_table.setRowCount(len(drugs))
        for row, drug in enumerate(drugs):
            for col, data in enumerate(drug):
                self.inventory_table.setItem(row, col, QTableWidgetItem(str(data)))

    def add_drug_to_db(self):
        name = self.drug_name.text()
        barcode = self.drug_barcode.text()
        qty = self.drug_qty.value()
        price = float(self.drug_price.text())
        expiry = self.drug_expiry.date().toString("yyyy-MM-dd")

        if not all([name, barcode, qty > 0, price > 0]):
            QMessageBox.warning(self, "Input Error", "Please fill all fields correctly.")
            return
        
        if db.add_drug(name, barcode, qty, price, expiry):
            self.load_inventory_data()
        else:
            QMessageBox.warning(self, "Database Error", "A drug with this barcode already exists.")

# Main execution block at the end of the file
if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = PharmacyApp()
    window.show()
    sys.exit(app.exec_())

# Hashtags: #PyQt5 #GUI #CRUD #Inventory

---

#Step 3: Point of Sale (POS) UI and Barcode Handling

Now, let's build the user interface for the sales tab. This will include an input for the barcode, a table for the current sale items (the "cart"), and buttons to finalize or clear the sale. A physical barcode scanner typically emulates a keyboard, entering the numbers and pressing "Enter". We will simulate this with the returnPressed signal on a QLineEdit.

Add these methods to the PharmacyApp class:

# In __init__, call the setup method
self.setup_pos_ui()
self.current_sale_items = {} # Dictionary to store {drug_id: {data, quantity}}

def setup_pos_ui(self):
    main_layout = QHBoxLayout()

    # Left side: Sale and Barcode input
    left_layout = QVBoxLayout()
    
    barcode_group = QGroupBox("Scan Barcode")
    barcode_layout = QVBoxLayout()
    self.barcode_input = QLineEdit()
    self.barcode_input.setPlaceholderText("Scan or type barcode and press Enter...")
    self.barcode_input.returnPressed.connect(self.add_item_to_sale)
    barcode_layout.addWidget(self.barcode_input)
    barcode_group.setLayout(barcode_layout)
    
    self.sales_table = QTableWidget()
    self.sales_table.setColumnCount(5)
    self.sales_table.setHorizontalHeaderLabels(['ID', 'Name', 'Quantity', 'Unit Price', 'Total Price'])
    
    left_layout.addWidget(barcode_group)
    left_layout.addWidget(self.sales_table)
    
    # Right side: Totals and Actions
    right_layout = QVBoxLayout()
    
    total_group = QGroupBox("Sale Summary")
    total_form = QFormLayout()
    self.total_amount_label = QLabel("0.00")
    total_form.addRow("Total Amount:", self.total_amount_label)
    total_group.setLayout(total_form)
    
    complete_sale_btn = QPushButton("Complete Sale")
    complete_sale_btn.clicked.connect(self.complete_sale)
    clear_sale_btn = QPushButton("Clear Sale")
    clear_sale_btn.clicked.connect(self.clear_sale)
    
    right_layout.addWidget(total_group)
    right_layout.addWidget(complete_sale_btn)
    right_layout.addWidget(clear_sale_btn)
    right_layout.addStretch()
    
    main_layout.addLayout(left_layout, stretch=3) # Left side takes 3/4 of space
    main_layout.addLayout(right_layout, stretch=1) # Right side takes 1/4
    
    self.pos_tab.setLayout(main_layout)

#Hashtags: #PointOfSale #BarcodeScanner #UIUX #PyQt5

---

#Step 4: Implementing the Sales Logic

This is the core logic that connects the barcode input to the sales table and the database. When a barcode is entered, we find the drug, add it to the current sale, and update the UI. The "Complete Sale" button will finalize the transaction by updating the database.

Add these methods to the PharmacyApp class:

def add_item_to_sale(self):
    barcode = self.barcode_input.text()
    if not barcode:
        return
    
    drug = db.find_drug_by_barcode(barcode)
    
    if not drug:
        QMessageBox.warning(self, "Not Found", "No drug found with this barcode.")
        self.barcode_input.clear()
        return
    
    drug_id = drug[0]
    
    if drug[3] <= 0: # Check quantity
         QMessageBox.warning(self, "Out of Stock", f"{drug[1]} is out of stock.")
         self.barcode_input.clear()
         return

    if drug_id in self.current_sale_items:
        # Item already in sale, increment quantity
        self.current_sale_items[drug_id]['quantity'] += 1
    else:
        # Add new item to sale
        self.current_sale_items[drug_id] = {
            'data': drug,
            'quantity': 1
        }
    
    self.update_sales_table()
    self.barcode_input.clear()

def update_sales_table(self):
    self.sales_table.setRowCount(len(self.current_sale_items))
    total_sale_amount = 0.0
    
    for row, item in enumerate(self.current_sale_items.values()):
        drug_data = item['data']
        quantity = item['quantity']
        unit_price = drug_data[4]
        total_price = quantity * unit_price
        
        self.sales_table.setItem(row, 0, QTableWidgetItem(str(drug_data[0]))) # ID
        self.sales_table.setItem(row, 1, QTableWidgetItem(drug_data[1]))      # Name
        self.sales_table.setItem(row, 2, QTableWidgetItem(str(quantity)))
        self.sales_table.setItem(row, 3, QTableWidgetItem(f"{unit_price:.2f}"))
        self.sales_table.setItem(row, 4, QTableWidgetItem(f"{total_price:.2f}"))
        
        total_sale_amount += total_price
        
    self.total_amount_label.setText(f"{total_sale_amount:.2f}")

def complete_sale(self):
    if not self.current_sale_items:
        return

    for drug_id, item in self.current_sale_items.items():
        db.update_drug_quantity(drug_id, item['quantity'])
    
    QMessageBox.information(self, "Success", f"Sale completed. Total: {self.total_amount_label.text()}")
    
    self.clear_sale()
    self.load_inventory_data() # Refresh inventory tab to show new quantities

def clear_sale(self):
    self.current_sale_items.clear()
    self.update_sales_table()

#Hashtags: #BusinessLogic #PointOfSale #PythonCode #Transaction

---

#Step 5: Results and Discussion

With all the code in place, you have a fully functional pharmacy management system.

How to Use It:
• Run the main.py noscript.
• Go to the "Inventory Management" tab and add a few drugs with unique barcodes.
• Go to the "Point of Sale" tab. The cursor will be in the barcode input field.
• Type a barcode of a drug you added and press Enter. The drug will appear in the sales table.
• Scan the same barcode again. The quantity for that drug in the sales table will increase to 2.
• Click "Complete Sale". A success message will appear. The sales table will clear.
• Switch back to the "Inventory Management" tab. You will see that the quantity of the sold drugs has decreased accordingly.

Discussion and Potential Improvements:
Real Barcode Scanner: This application works directly with a USB barcode scanner. A scanner acts as a keyboard, so when it scans a code, it types the numbers and sends an "Enter" keystroke, which perfectly triggers our returnPressed signal.
Data Integrity: We added a basic check for stock (quantity > 0). A more robust system would check if the quantity in the cart exceeds the quantity in stock before allowing the sale to complete.
Features for a Real Pharmacy: A production-level system would need many more features: prenoscription management, patient records, batch tracking for recalls, advanced reporting (e.g., top-selling drugs, low-stock alerts), user accounts with different permission levels, and receipt printing.
Database: SQLite is perfect for a single-user, standalone application. For a pharmacy with multiple terminals, a client-server database like PostgreSQL or MySQL would be necessary.

This project provides a solid foundation, demonstrating how to integrate hardware (like a barcode scanner) with a database-backed desktop application to solve a real-world business problem.

#ProjectComplete #SoftwareEngineering #PythonGUI #HealthTech

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By: @DataScienceN ✨

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💡 Top 70 Web Scraping Operations in Python

I. Making HTTP Requests (requests)

• Import the library.

import requests

• Make a GET request to a URL.

response = requests.get('http://example.com')

• Check the response status code (200 is OK).

print(response.status_code)

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html_bytes = response.content

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html_text = response.text

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• Import the library.

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noscript_tag = soup.noscript

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noscript_parent = soup.noscript.parent

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III. Finding Elements with BeautifulSoup