When building mobile applications, one of the most common requirements is to store data locally on the device. While cloud databases and APIs provide flexibility for remote storage, many applications also need to manage data offline. This is where SQLite comes in.

SQLite is a lightweight relational database engine that is embedded directly into mobile devices. Unlike large-scale database systems such as MySQL or PostgreSQL, SQLite does not require a server. It runs inside the application itself, making it efficient, fast, and perfect for mobile use cases.

In the Flutter ecosystem, developers can use SQLite through a popular package called sqflite. This package provides a simple and efficient way to perform database operations such as creating tables, inserting records, querying data, updating rows, and deleting entries. SQLite is ideal for storing structured, relational data where queries and indexing are important.

Understanding SQLite

Before diving into how it works in Flutter, let us first understand what SQLite actually is.

SQLite is a software library that provides a relational database management system (RDBMS). Unlike traditional RDBMS systems, it does not run as a separate process or require a dedicated server. Instead, it is embedded into applications. The database itself is stored in a single file on the device, making it easy to use, portable, and lightweight.

Some key features of SQLite include:

Relational database with support for tables, rows, columns, and SQL queries.
Serverless design, as it runs inside the app process.
Single-file storage, where the entire database is contained in one file.
ACID compliance, which means it guarantees atomicity, consistency, isolation, and durability.
Cross-platform support, working on Android, iOS, Windows, Linux, and macOS.

These features make SQLite a perfect match for mobile applications that need robust local storage.

Why SQLite is Important in Mobile Applications

Mobile apps often need to store data locally for multiple reasons. Some of the most common include:

Offline access, allowing users to access the app even without internet connectivity.
Faster access, since retrieving data from local storage is much quicker than calling remote APIs.
Relational structure, making it easy to organize data into tables and query it efficiently.
Reduced dependency on servers, which improves app performance and lowers backend costs.

Examples of applications that typically use SQLite include note-taking apps, personal finance apps, task managers, and even large e-commerce apps where caching product data locally can reduce network usage.

SQLite in Flutter

Flutter is Google’s open-source framework for building cross-platform mobile, web, and desktop applications. Since Flutter supports both Android and iOS, developers need a database solution that works seamlessly across both platforms. SQLite is available on both Android and iOS by default, and Flutter developers can access it using the sqflite plugin.

The sqflite package is the most popular and widely used SQLite plugin in Flutter. It provides a simple Dart API to manage databases using SQL commands. Developers can create tables, insert records, update rows, and query results without needing platform-specific code.

Installing the sqflite Package

To use SQLite in Flutter, the first step is installing the sqflite package. This can be done by adding the following dependency to the pubspec.yaml file:

dependencies:
  sqflite: ^2.3.0
  path: ^1.8.3

The path package is also recommended because it helps define file paths in a platform-independent way. This ensures that the database file is stored correctly in both Android and iOS.

After saving the file, run flutter pub get to install the dependencies.

Creating and Opening a Database

The first step in working with SQLite is creating and opening a database. With the sqflite package, this can be done as follows:

import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';

Future<Database> openDatabaseConnection() async {
  final databasePath = await getDatabasesPath();
  final path = join(databasePath, 'example.db');

  return openDatabase(
path,
version: 1,
onCreate: (db, version) {
  return db.execute(
    "CREATE TABLE users(id INTEGER PRIMARY KEY, name TEXT, age INTEGER)",
  );
},  );
}

This code demonstrates how to:

Get the default path for databases using getDatabasesPath().
Define the full path by joining the database directory with the file name.
Call openDatabase() to create or open the database file.
Provide an onCreate callback that runs when the database is created for the first time, allowing us to create tables.

Inserting Data into SQLite

Once the database and tables are ready, the next step is inserting data. In SQLite, this is done with SQL INSERT statements. With sqflite, we can use Dart’s map structure to pass data easily.

Future<void> insertUser(Database db, Map<String, dynamic> user) async {
  await db.insert(
'users',
user,
conflictAlgorithm: ConflictAlgorithm.replace,  );
}

Here, the insert() function takes the table name, a map of values, and a conflict resolution algorithm. The conflict algorithm ensures that if a record with the same primary key exists, it will be replaced instead of throwing an error.

An example of inserting a user would look like this:

final user = {'id': 1, 'name': 'Alice', 'age': 25};
await insertUser(db, user);

Querying Data from SQLite

The most powerful feature of relational databases is querying data. With SQLite in Flutter, we can use the query() function to fetch rows from a table.

Future<List<Map<String, dynamic>>> getUsers(Database db) async {
  return await db.query('users');
}

This function retrieves all rows from the users table and returns them as a list of maps. Each map represents a row with column names as keys.

For example, after inserting some users, calling getUsers(db) might return:

[
  {'id': 1, 'name': 'Alice', 'age': 25},
  {'id': 2, 'name': 'Bob', 'age': 30}
]

Updating Data in SQLite

Updating data in SQLite is straightforward with the update() method.

Future<void> updateUser(Database db, Map<String, dynamic> user) async {
  await db.update(
'users',
user,
where: 'id = ?',
whereArgs: &#91;user&#91;'id']],  );
}

Here, we specify the table name, the new values, and a where condition to identify which rows should be updated. This ensures that only the matching row is modified.

Deleting Data from SQLite

To remove data, we can use the delete() method.

Future<void> deleteUser(Database db, int id) async {
  await db.delete(
'users',
where: 'id = ?',
whereArgs: &#91;id],  );
}

This function deletes the user with the matching ID from the table. Deletion is often combined with queries to clean up data when users remove items or accounts.

Using Raw SQL Queries

While helper methods like insert(), update(), and query() simplify operations, the sqflite package also allows raw SQL queries for more flexibility.

For example:

Future<List<Map<String, dynamic>>> getUsersAboveAge(Database db, int minAge) async {
  return await db.rawQuery('SELECT * FROM users WHERE age > ?', [minAge]);
}

This allows advanced queries with conditions, joins, and aggregations.

Use Cases of SQLite in Flutter Apps

SQLite is used in a wide variety of Flutter applications. Some common use cases include:

Note-taking apps where user notes are stored locally for offline access.
Task managers or to-do list apps that keep track of tasks.
Finance or expense tracking apps where users record transactions.
E-commerce apps that cache product data for faster browsing.
News apps that save articles locally for offline reading.
Chat applications that store message history locally.

The versatility of SQLite makes it a go-to solution for developers building apps with structured offline data requirements.

Advantages of SQLite in Flutter

Lightweight and fast, making it suitable for mobile devices.
Cross-platform compatibility across Android and iOS.
Simple integration with Flutter through the sqflite package.
Supports relational data and SQL queries.
Provides durability and reliability with ACID compliance.
Works offline without internet connectivity.
Easy to set up with no need for server configuration.

Limitations of SQLite in Flutter

Although SQLite is powerful, it is not without limitations. Some of the key challenges include:

It may not handle very large-scale data well, especially compared to server databases.
No built-in support for advanced features such as stored procedures or user-defined functions.
Complex queries with multiple joins can become harder to manage.
It requires developers to write SQL, which may be challenging for those unfamiliar with databases.
Concurrency management can be tricky in multi-threaded environments.

For simple to moderately complex mobile apps, however, SQLite is more than sufficient.

Best Practices for Using SQLite in Flutter

When working with SQLite in Flutter applications, it is important to follow best practices to ensure efficiency and maintainability:

Use the path package to define database file locations consistently.
Create a dedicated database helper class to organize database logic.
Always close the database when it is no longer needed to free resources.
Use transactions for multiple operations to ensure consistency.
Avoid blocking the main UI thread with database operations; use asynchronous functions.
Keep SQL queries simple and optimized.
Use indexing on frequently queried columns for performance improvements.

Alternatives to SQLite in Flutter

While SQLite is widely used, Flutter also supports other database and storage options depending on the application’s requirements. Some alternatives include:

Hive, a lightweight NoSQL database written in pure Dart, optimized for speed.
ObjectBox, a high-performance NoSQL database with reactive APIs.
SharedPreferences, for storing small key-value pairs instead of complex data.
Moor (Drift), a higher-level abstraction on top of SQLite that provides type safety and reactive queries.

What is SQLite in Flutter?