What are transactions in IndexedDB and why are they important?

Question

ICSM Computer · Answer

In IndexedDB, a transaction is a wrapper around one or more operations that ensures
data integrity and consistency. All read and
write operations must happen inside a transaction.
Why Are Transactions Important?
Atomicity: All operations in a transaction succeed or fail together.Isolation: Prevents conflicts from simultaneous operations.Lifetime-controlled: Transactions auto-close after completing or timing out.Required: You must use a transaction to read/write from object stores.
Syntax and Usage
const tx = db.transaction(['store1', 'store2'], 'readwrite');
const store = tx.objectStore('store1');
store.put({ id: 1, name: 'Alice' });
Parameters:
Store(s): A string or array of object store names.Mode: "readonly" or "readwrite"
Transaction Example
const tx = db.transaction('users', 'readwrite');
const store = tx.objectStore('users');
store.add({ id: 1, name: 'Alice' });
store.put({ id: 1, name: 'Alice Updated' });
store.delete(2); // Optional: delete by id
tx.oncomplete = () =andgt; {
    console.log('Transaction complete.');
};
tx.onerror = () =andgt; {
    console.error('Transaction failed:', tx.error);
};
Transaction Modes
Mode
Description
readonly
Can only read data
readwrite
Can read and write
Key Transaction Rules
Transactions auto-commit once all operations finish.You cannot reuse a transaction once it's completed or errored.Do not do async calls (like fetch) inside a transaction and expect the transaction to stay open — it
will close immediately.
Tip: Multiple Stores in One Transaction
const tx = db.transaction(['users', 'orders'], 'readwrite');
const users = tx.objectStore('users');
const orders = tx.objectStore('orders');
users.put({ id: 1, name: "Alice" });
orders.add({ orderId: 101, userId: 1 });
This ensures both operations succeed or fail together.
Summary
Transactions are mandatory for all DB operations.Ensure atomic, consistent changes.Must be used with the correct mode and store name(s).Automatically manage their lifecycle.

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What are transactions in IndexedDB and why are they important?

ICSM Computer

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1 Answers

Why Are Transactions Important?

Syntax and Usage

Parameters:

Transaction Example

Transaction Modes

Key Transaction Rules

Tip: Multiple Stores in One Transaction

Summary

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