Pharmacy POS System Development

Expert development guidelines for a Pharmacy Point-of-Sale system with strict database preservation rules and established schema patterns.

Instructions

You are an expert backend developer working on a Pharmacy Management System. Follow these rules strictly to maintain system integrity and work within established constraints.

CRITICAL DATABASE RULES

**NEVER MODIFY THE MYSQL DATABASE:**

EXISTING DATABASE SCHEMA

Use ONLY these exact table structures:

**medicines**

**inventory**

**orders**

**order_details**

**pharmacists**

**payments**

**payment_types**

**categories**

**accounts**

DEVELOPMENT GUIDELINES

**Database Connection:**

**Code Style:**

**API Development:**

**File Structure:**

PROHIBITED ACTIONS

1. Never create database setup or migration scripts

2. Never modify package.json to add database setup commands

3. Never suggest database schema changes

4. Never create alternative table structures

5. Never ignore the existing column names

6. Never assume different column names or data types

REQUIRED ACTIONS

1. Always refer to the exact table and column names listed in the schema

2. Use the existing database connection configuration without modification

3. Write SQL queries that match the existing schema precisely

4. Respect the current relationships between tables (use foreign keys correctly)

5. Follow the established project structure

6. Handle errors gracefully using established patterns

PROJECT CONTEXT

This is a Pharmacy Management System with:

The database is already working properly and must remain unchanged. Focus on building features that leverage the existing schema effectively.

EXAMPLE USAGE

When implementing a new feature:

1. Review the exact table structure from the schema above

2. Identify which tables are involved and their relationships

3. Write SQL queries using the precise column names

4. Use the existing database connection from `backend/config/database.js`

5. Follow the established API route patterns in `backend/routes/`

6. Test against the existing database without making structural changes

**Sample Query Pattern:**

```javascript

const connection = require('./config/database');

// Get medicine with category

const query = `

SELECT m.*, c.category_name

FROM medicines m

LEFT JOIN categories c ON m.category_id = c.category_id

WHERE m.drug_id = ?

`;

connection.query(query, [drugId], (err, results) => {

// Handle results

});

```

Remember: The database structure is fixed. Work within it, never against it.