Query-Based Access Control: How to Control Data Without Touching the Code
Hey buddy, let's chat a bit about the design system that lets you sleep soundly 🧠⚙️
Imagine you have a system with millions of records and users with different roles: Admin, HR, Manager, Regular User... It's quite something! They all see the same table, but not the same data.
Alright, a simple yet tricky example. Imagine you're viewing the employee list:
- You see the employee list? Sure ✅
- You see the salary? No ❌
- You see the address? Maybe
- You see the national ID? Depends on the role
And the rest is up to you; here's where the trouble begins 👀
If every time you have to write:
```php
if ($user->isAdmin()) { select *
} else { select name, email
}
```
You've entered a nightmare: - Code full of if/else - Hard to maintain - Any permission change = code modification + deployment - Endless bugs - Security holes if you forget a condition 😬 This is not System Design... it's organized chaos.
The Real Problem
The problem isn't with the Users or the Records; it's that you've tied permissions to the code. The right way is to move permissions to the data itself, not the application.
The Smart Solution: Query-based Access Control 🧩
The brilliant idea here is that the Admin, not the Developer, defines the rules. What does this mean?
The Admin has a screen where they can:
- Write a Query
- Select Fields
- Define a View
- Link it to a User or Role
For example:
```sql
SELECT id, name, email, department
FROM employees
```
And for another regular User:
```sql
SELECT id, name, email, department, salary
FROM employees
```
That's it. Without touching a single line of code 🔥
So, how do you implement this?
1️⃣ Row / Column Level Security
In practice, you:
- Use Dynamic Queries
- SQL Views
- Stored Queries saved in the DB
The User gets access to the Query, not the Table
2️⃣ Clever Use of CTEs 💡
In the backend:
- Gather all the queries the user is allowed to use
- Combine them using WITH (CTE)
- Return a final Result
A simple example:
```sql
WITH allowed_data AS (
-- queries user has access to
)
SELECT * FROM allowed_data;
```
This way:
- No matter what the user tries
- No matter how they play with the Request
- They will only see what the Query allows
- Security by design 🔐
The Major Advantage Here 🔥
❌ No if/else in the code
❌ No fear of forgetting a Field
✅ Permissions change at Runtime
✅ Admin can add/modify without Deployment
✅ Scales easily with millions of Records
This is the difference between:
- CRUD Developer 👶 - System Designer 🧔♂️🔥
So, what are the drawbacks? (To be completely honest)
Ah, this solution:
- Is a bit complex at first
- Requires strong validation on the queries
- Must completely prevent SQL injection
- Needs proper logging
But...
- The complexity is justified here
- Once you get it right, you end up with a system that is:
- Secure
- Flexible
- Enterprise-ready
Summary 🧠
If your system:
- Has sensitive data
- Involves many roles
- Has permissions that change
- You want to sleep soundly
Then:
- Don't tie permissions to the code
- Tie them to the queries
- And when you feel the system is working with you... not against you 😎