Why transactions are needed in MongoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a transaction in MongoDB.

MongoDB

const session = client.startSession();
session.[1]();

Drag options to blanks, or click blank then click option'

AstartTransaction

BbeginTransaction

CopenTransaction

DinitTransaction

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'beginTransaction' instead of 'startTransaction'.

Trying to call 'openTransaction' which does not exist.

In MongoDB, startTransaction() is the correct method to begin a transaction session.

2fill in blank

medium

Complete the code to commit a transaction in MongoDB.

MongoDB

await session.[1]();

Drag options to blanks, or click blank then click option'

AcommitTransaction

BsaveTransaction

Ccommit

DfinalizeTransaction

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'commit' instead of 'commitTransaction'.

Trying to use 'saveTransaction' which is not a valid method.

The method commitTransaction() commits the changes made in the transaction.

3fill in blank

hard

Fix the error in the code to abort a transaction properly.

MongoDB

await session.[1]();

Drag options to blanks, or click blank then click option'

ArollbackTransaction

BabortTransaction

CcancelTransaction

DstopTransaction

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'rollbackTransaction' which is not a MongoDB method.

Trying 'cancelTransaction' or 'stopTransaction' which do not exist.

The correct method to abort a transaction in MongoDB is abortTransaction().

4fill in blank

hard

Fill both blanks to correctly use a transaction with a session in MongoDB.

MongoDB

const session = client.startSession();
try {
  session.[1]();
  await collection.insertOne(doc, { session: [2] });
  await session.commitTransaction();
} finally {
  await session.endSession();
}

Drag options to blanks, or click blank then click option'

AstartTransaction

Bsession

CcommitTransaction

DabortTransaction

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'commitTransaction' in the first blank instead of 'startTransaction'.

Passing something other than 'session' in the operation options.

We start the transaction with startTransaction() and pass the session object to the operation.

5fill in blank

hard

Fill all three blanks to handle a transaction with error handling in MongoDB.

MongoDB

const session = client.startSession();
try {
  session.[1]();
  await collection.updateOne(filter, update, { session: [2] });
  await session.[3]();
} catch (error) {
  await session.abortTransaction();
} finally {
  await session.endSession();
}

Drag options to blanks, or click blank then click option'

AstartTransaction

Bsession

CcommitTransaction

DabortTransaction

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'abortTransaction' in the third blank instead of 'commitTransaction'.

Not passing the session object in the operation options.

We start the transaction with startTransaction(), pass the session to the update operation, and commit with commitTransaction().