Realtime Database vs Firestore decision in Firebase - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize a Firestore database instance.

Firebase

const db = firebase.firestore().[1]();

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Asettings

Bdoc

Cget

Dcollection

Attempts:

3 left

💡 Hint

Common Mistakes

Using collection() or doc() instead of settings() to configure Firestore.

The settings() method is used to configure Firestore settings after initialization.

2fill in blank

medium

Complete the code to listen for realtime updates in Realtime Database.

Firebase

database.ref('messages').[1](snapshot => { console.log(snapshot.val()); });

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Aonce

Bget

Con

Dset

Attempts:

3 left

💡 Hint

Common Mistakes

Using once() which only fetches data once instead of listening continuously.

The on() method listens continuously for data changes in Realtime Database.

3fill in blank

hard

Fix the error in Firestore query to get documents where age is greater than 18.

Firebase

db.collection('users').where('age', '[1]', 18).get().then(snapshot => { /* handle data */ });

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A>

B==

C<=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' which only matches exact age 18.

Using '<=' or '<' which filter younger users.

The where clause uses '>' to filter documents with age greater than 18.

4fill in blank

hard

Fill both blanks to write a Firestore query that orders users by name and limits to 5 results.

Firebase

db.collection('users').[1]('name').[2](5).get();

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AorderBy

Blimit

Cwhere

DstartAt

Attempts:

3 left

💡 Hint

Common Mistakes

Using where instead of orderBy for sorting.

Using startAt instead of limit to restrict results.

orderBy('name') sorts the results by name, and limit(5) restricts to 5 documents.

5fill in blank

hard

Fill all three blanks to write Realtime Database code that updates user age, sets a listener, and removes a user.

Firebase

database.ref('users/[1]').[2]({ age: 30 });
database.ref('users').[3](snapshot => { console.log(snapshot.val()); });
database.ref('users/[1]').remove();

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Auser123

Bupdate

Con

Dset

Attempts:

3 left

💡 Hint

Common Mistakes

Using set() instead of update() which overwrites data.

Using once() instead of on() for listening.

We update user 'user123' with update(), listen for changes with on(), and remove the same user.