States of Transactions

A transaction goes through several states from beginning to end. Understanding these states helps you know when changes are temporary or permanent, and when things can go wrong.

🔄 Active State

• The transaction has started.

• It is executing SQL commands like SELECT, UPDATE, INSERT, or DELETE.

🟢 Example: You start transferring money. Debit from one account is in progress.

⏳ Partially Committed State

• The transaction has completed its final operation.

• It is ready to commit, but the changes are not yet saved permanently to the database.

🟡 Example: ₹500 has been deducted but not yet credited. You're about to hit "Confirm".

✅ Committed State

• The transaction is successfully completed.

• All changes are saved permanently in the database.

🟢 Example: ₹500 is debited from A and credited to B. Confirmation received.

After this, the transaction cannot be undone, even if a system crash occurs.

❌ Failed State

• Something went wrong before completion.

• This could be due to:

  • System crash

  • Power failure

  • Constraint violation

  • Software error

🔴 Example: While crediting the amount, the system crashes or connection drops.

🔁 Aborted State

• The failed transaction is rolled back.

• The database is restored to its original state (before the transaction began).

• The transaction may be restarted or discarded.

🟠 Example: ₹500 is re-added to A's account, and the transaction is canceled.

🧭 Transaction State Diagram (Text Format)

📌 Summary Table