Why Realtime Database differs from Firestore in Firebase - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize a Firebase Realtime Database reference.

Firebase

const dbRef = firebase.database().ref([1]);

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

A'firestore'

B'collections'

C'users'

D'documents'

Attempts:

3 left

💡 Hint

Common Mistakes

Using Firestore terms like 'collections' or 'documents' instead of Realtime Database paths.

The Realtime Database uses references to paths like 'users' to access data.

2fill in blank

medium

Complete the code to initialize a Firestore collection reference.

Firebase

const colRef = firebase.firestore().collection([1]);

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

A'database'

B'users'

C'realtime'

D'usersNode'

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing Realtime Database paths with Firestore collections.

Firestore uses collections like 'users' to organize documents.

3fill in blank

hard

Fix the error in the code to listen for realtime updates in Firestore.

Firebase

colRef.onSnapshot([1]);

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

A(snapshot) => { console.log(snapshot.docs); }

Bfunction() { console.log('update'); }

Con('value', callback)

DaddListener('change', callback)

Attempts:

3 left

💡 Hint

Common Mistakes

Using Realtime Database event listeners like 'on' or 'addListener'.

Firestore uses onSnapshot with a callback receiving a snapshot object.

4fill in blank

hard

Fill both blanks to write a query that gets users older than 18 in Firestore.

Firebase

const query = firebase.firestore().collection('users').where([1], [2], 18);

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

A'age'

B'name'

C'>'

D'=='

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong field names or operators like '==' instead of '>'.

Firestore queries use where(field, operator, value). Here, field is 'age' and operator is '>'.

5fill in blank

hard

Fill all three blanks to write code that updates a user's name in Realtime Database.

Firebase

firebase.database().ref([1]).update({ [2]: [3] });

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

A'users/user123'

B'name'

C'Alice'

D'age'

Attempts:

3 left

💡 Hint

Common Mistakes

Using Firestore paths or wrong keys like 'age' instead of 'name'.

To update a user's name, reference the path 'users/user123', set the key 'name' to the new value 'Alice'.