Using Firebase with Flutter for CRUD Operations

Kanika Ratra
Mar 1 · 3 min read

Flutter is booming in the mobile market as the next revolution. It has proven to hold the potential to win over every mobile technology and become the only choice for cross-platform app development in the future. In this article we will add Cloud Firestore to our Flutter application, perform different read, and write operation . To follow along it is crucial to understand JSON first.

What is JSON and Why do we need it ?

JSON stands for javascript object notation, it is a data-interchange format which is used for the communication purposes between two platforms . Now, the question arises why do we need JSON? It is analogous in a way how global trade runs in U.S dollars. It can become really cumbersome as each country has different currency and we need some common ground to ensure trading, thus the system agreed on U.S dollars.

In a similar way in our technological world the systems agree on a single format for data to be exchanged and use common ground i.e JSON .

Format of data to be stored in Firebase:

The model of the data looks like :

We want to have a collection named Weights having document corresponding to each user having a list of Weight model. Our weight model includes dummy data as date, weight and id.

Adding Data to Firestore:

Before beginning with storing data , we need to understand what type of data is stored in Firestore.

Firestore stores the Data in JSON format , so we have to pass JSON to it.

Since we want to have document corresponding to each user , we need to specify the document name . Variable defined as UID is defined globally in the class, which is used later to create , read , update and delete.

2. Before updating data for the first time , let’s understand how to structure the data we want to store and then how to store data would be a simple step.

Step 1 : is to structure the data -

{ListOfWeight: [{date: 19/02/2021, weight: 23.0, id: 02}, {date: 23/02/2021, weight: 24.0, id: 03}]}

Step 2: use set command- To Update data for the first time use set command -

Reading Data From Firestore:

Reading data plays a crucial role and it is really important to have the clear picture about it. The data from firestore is returned in a document snapshot , whose data property has our stored data which can be further manipulated.

Append Data to List in Firestore:

The arrays are updated using FieldValue. arrayUnion() provided by firestore.

Delete Data from List in Firestore:

The element from array are removed using FieldValue. arrayRemove() provided by firestore.

Hope this article helps you. Please don’t forget to clap, thanks in advance.

Please refer the source code below:

In case of any doubt , feel free to reach me .

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Kanika Ratra

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Tech Explorer | Flutter Fan | Learning keeps you in the Lead

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