Data Persistence with SQLite | Flutter
Whenever you need to store the data on the local then you need to use SQLite to persist the user data.
Why Data Persistence?
Persisting data is important for users since it would be inconvenient for them to type their information every time or wait for the network to load the same data again. In situations like this, it would be better to save their data locally.
Why we use SQLite?
SQLite is a popular choice as embedded database software for local/client storage in application software such as web browsers.
How to use SQLite in a flutter?
Before using SQLite, you should know that
SQLite is not available in a flutter SDK as Android but we have a plugin
sqflite that exactly performs all the operation on the database just like in Android and iOS.
Flutter plugin is the wrapper of the native code written in Kotlin or java for Android and swift or objective-c for iOS.
P.S : Plugin can also be created only with dart code
If you are new to SQLite, go through SQLite Tutorial site here.
Step 1: Add the dependencies
To work with SQLite databases, import the
sqflite package provides classes and functions that allow you to interact with a SQLite database.
path_provider package provides functions that allow you to correctly define the location to store the database on disk such as
Step 2: Create a Model class
SQLite creates a table for the model class, the fields in the class correspond to columns in the table. Therefore, the classes tend to be small model classes that don’t contain any logic. Our
Person class represents the model for the data in the database.
If we want to insert into the database then we need to convert the
Person into a
And if we want to retrieve from the database then we need to convert the
Map into the
This is how our PODO class will look like
Step 3: Create a database
We will make a separate class as database.dart to make the code more modular and add all the requirements meths for managing the database that can be accessed anywhere in the app.
Create a singleton class
We use the singleton pattern to ensure that we have only one class instance and provide global point access to it.
How to create a Singleton in Dart?
Create a private constructor that can be used only inside the class.
Step 4: Open the Database
Before you read and write data to the database, you need to open a connection to the database. This involves two steps:
1. Define the path to the database file using the
getDatabasesPath from the
sqflite package combined with the
pathfunction from the
2. Open the database with the
openDatabase function from
Step 5: Create the table
You need to create a table to store information.
For example, In our case, we create a table called
Person that defines the data that can be stored. In this case, each
Person contains an
city. Therefore, these will be represented as three columns in the
id is a Dart
int, and will be stored as an
INTEGER SQLite Datatype. It is also good practice to use an
id as the primary key for the table to improve query and update times.
name is a Dart
String, and will be stored as a
TEXT SQLite Datatype
city is also a Dart
String, and will be stored as an
To prevent from opening a connection to the database again and again we can use this:
Step 6: Managing the data
Now we are going to show you how you can perform an operation on the SQLite database.
getAllPersons() will return all the person from the SQLite database if available.
If you see we have two methods, one deletes the row with particular id and other deletes all data present in the table, you can change all the query according to your need.
If these small code snippets still confuse you we have the complete code of the database class:
Step 7: Using the data
In order to use the database we need to create the instance of the database and use the method present in the database class
This will help us to perform an operation on the database.
like if we want to get the person in the database we will use the method that we have defined in our DatabaseProvider class
And if I want to display it in the list then I’ll use FututeBuilder :
That it for SQLite in flutter.
Thanks for reading this article
If we got something wrong? Let me in the comments. we would love to improve.
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