Firebase : Questions for TechPrep

[Riyaz1000]

1. What is Firebase?

Answer : Google Firebase is a Google-backed app development platform that allows developers to create apps for iOS, Android, and the web. Firebase Realtime Database (Firebase) is a cloud-based NoSQL database that syncs and stores data in real-time across users. Firebase, developed by Google and released in 2017, allows for expressive searches that scale with the size of the result set via Android, iOS, and JavaScript SDKs.

2. What is Firebase architecture?

Answer : Firebase lies between the server and the clients in this architecture. Servers can connect to Firebase and interact with its data in the same way that any other client can. To put it another way, the server interacts with clients by modifying data in Firebase. Integrating with Firebase is simple if developing server code in Node.JS. The API of our Node.JS library is identical to that of our JS SDK. If using a different language or framework, we may use our REST API to save and retrieve Firebase data from any environment that supports HTTPS queries.

3. Is firebase frontend or backend?

Answer : Since Firebase is a backend solution, users can do anything on backend with the Firebase admin sdk.

4 . What are the features of Firebase?

Answer : There are different features available in Robot Framework.

Tabular format for test cases
The test cases in the Robot framework are defined in a simple tabular manner using keywords.
Incredibly Built-In Analytics
It supports unlimited reporting, audience segmentation, integration with other services.
App Development Made Easy
It provides cloud messaging, authentication, test lab, remote configuration, dynamic links, crash reporting, real-time database, storage features.
Growth and User Engagement
It made easy to link AdWords. Supports App indexing, invites referrals easily, and can provide notifications.

5 . What is the difference between Firebase and MongoDB ?

Answer:

Firebase	Mongodb
Google developed Firebase in 2012.	MongoDB Inc. developed Mongo in 2009.
Firebase supports programming languages like Objective C, Java, and JavaScript.	MongoDB supports programming languages like C, C#, Java, JavaScript, PHP, Lua, Python, R, Ruby.
Firebase is a commercial database.	MongoDBis an open-source database.
Firebase's server operating systems are hosted	Solaris, Linux, OS X, and Windows are the server operating systems for MongoDB.
It does not support any techniques of replication.	MongoDB supports Master-Slave Replication as a replication technique.
The Map Reduce technique is not supported.	Map Reduce techniques are supported..
It doesn't have any partitioning options.	Sharding Partitioning is supported..
APIs and other access methods include Android, iOS, JavaScript API, and RESTful HTTP API.	APIs and other access methods utilize proprietary protocols based on JSON.
It's better suited for smaller applications.	It's better suited to large-scale applications.
It is not very secure.	It has better security than Firebase.

6 . What is the push method in firebase?

Answer: The Push() method creates a unique key each time a new child is added to the provided Firebase reference. Users can use the reference to the new data provided by the Push() method to get the value of the child's auto-generated key or set data for the child.

7 . What is the set() method in firebase?

Anwers : We can use the set() method to overwrites data at the specified location, with any child nodes

8 . Which method is used to update the firebase data?

Answer : We can utilize setValue() on the relevant child reference to update a single node in our JSON database.

9 . Is Firebase key value?

Answer : Anything in the Firebase Database is a node that follows the key: value pattern. We can generate unique keys with ease using Firebase Database. Unique keys generate new items, whereas data uploaded to a previously stored key updates it.

10. How can we create a unique key and use it to send data in Firebase?

Answer : We can use push() to establish a unique key in the Firebase database, and then add child nodes to that key. When you return to that activity in the future, check to see if the parent node is still present. Save the parent node key and use it to save new child nodes if the node already exists.

@string parentKey;
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("Employee");
databaseReference.addListenerForSingleValueEvent(new ValueEventListener() {
@OverRide
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot != null && dataSnapshot.exists()) {
// parent node exists, get parent node from datasnapshot
parentKey = dataSnapshot.value().toString();
} else {
// parent node doesn't exists, create parent node using push
parentKey = FirebaseDatabase.getInstance().getReference().child("Employee").push().getKey();
}
}

    @Override
    public void onCancelled(final DatabaseError databaseError) {
        onChildCheckListener.onChildDoesntExist();
		................
    }
});

You can now add child nodes using the parentKey as a reference.

String childKey = FirebaseDatabase.getInstance().getReference("Employee")
.child(parentKey).push().getKey();

10 . Does Firebase support descending sort order?

Answer : According to the documentation, there is no descending order in Firebase, it support ascending order:
orderByChild() : The children with a numeric value come next, in increasing order. If more than one child has the same numerical value for the same child node, the children are sorted by key.

We can use Collection.reverse(datalist) to perform descending sort order.

11 . How do I get particular data from Firebase?

Answer : // Get a reference to your user
final FirebaseDatabase database = FirebaseDatabase.getInstance(); DatabaseReference ref = database.getReference("server/path/to/profile");

// Attach a listener to read the data at your profile reference
`ref.addValueEventListener(new ValueEventListener() {
@OverRide
public void onDataChange(DataSnapshot dataSnapshot) {
Profile profile = dataSnapshot.getValue(Profile.class);
System.out.println(profile.getUsername());
}

@Override
public void onCancelled(DatabaseError databaseError) {
    System.out.println("The read failed: " + databaseError.getCode());
}

});`

12 . How to use Firebase Database REST API?

Answer : We can utilise any Firebase Realtime Database URL as a REST endpoint. Simply append.json to the end of the URL and send a request using your preferred HTTPS client.

It is necessary to use HTTPS. To keep your data safe, Firebase only responds to encrypted traffic.

For Example:
Get - Read the data

curl 'https://[PROJECT_ID].firebaseio.com/users/john/name.json'

A 200 OK HTTP status code indicates a successful request. The data corresponding with the path in the GET request is provided in the response.

{ "first": "John", "last": "Brook" }