Isolation in Databases

Isolation: Keeping Transactions Independent and Reliable

Think of a busy restaurant kitchen during peak hours. Multiple chefs are preparing different dishes at the same time. For the kitchen to run smoothly, each chef needs to work without being affected by what others are doing.

This is what isolation provides in a database: Each transaction runs in its own space, protected from the incomplete work of others.

What goes wrong without isolation?

Let’s say:

• Transaction A is updating a user’s account balance to $500.
• Before A finishes and commits,
• Transaction B reads the new balance of $500, assuming it's valid.

But if Transaction A fails and rolls back, B has acted on data that never truly existed. That’s called a dirty read—and it's a dangerous bug in critical systems.

With proper isolation:

Each transaction sees only committed data. Unfinished work is hidden.

Changes made inside a transaction become visible to others only after a successful commit.

Example:

Isolation ensures that transactions don’t interfere with each other. It’s how databases maintain order when everything runs at the same time.