31.3. Data Persistence with SQLite in Flutter: Creating and Managing Tables

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SQLite is a C library that provides a lightweight disk database that does not require a separate server process and allows you to access the database using a non-standard variant of SQL. In addition, SQLite also provides transactional interfaces for crash recovery.

In Flutter, one of the main uses of SQLite is data persistence. Data persistence is the process of storing data on a long-term storage medium, such as a database, so that it can be retrieved even after an application restart. SQLite is ideal for this purpose as it is lightweight, efficient and requires little configuration.

To start using SQLite in your Flutter app, you will need to add the sqlite package to your pubspec.yaml file. Next, you can import the sqlite package into your Dart file and start using it.

Creating Tables

To create a table in SQLite, you will use the db.execute() method. This method takes an SQL string that defines the table and its fields. For example:

db.execute(
  'CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT, age INTEGER)'
);

This code creates a table called 'users' with three fields: 'id', 'name' and 'age'. The 'id' field is defined as the primary key, which means that each record in the table will have a unique 'id'.

Table Management

Once you create a table, you can insert, update, delete and query records using the db.insert(), db.update(), db.delete() and db.query() methods respectively.

To insert a record, you can use the db.insert() method as follows:

db.insert(
  'users',
  {'name': 'John Doe', 'age': 30},
  conflictAlgorithm: ConflictAlgorithm.replace,
);

This code inserts a record into the 'users' table with the name 'John Doe' and age 30. If a record with the same 'id' already exists, it will be replaced.

To update a record, you can use the db.update() method. For example:

db.update(
  'users',
  {'name': 'Jane Doe', 'age': 25},
  where: 'id = ?',
  whereArgs: [1],
);

This code updates the record with 'id' 1, changing the name to 'Jane Doe' and the age to 25.

To delete a record, you can use the db.delete() method. For example:

db.delete(
  'users',
  where: 'id = ?',
  whereArgs: [1],
);

This code deletes the record with 'id' 1.

To query records, you can use the db.query() method. For example:

List

This code retrieves all records from the 'users' table.

In summary, SQLite is a powerful tool for persisting data in Flutter applications. It provides an efficient and easy way to create and manage database tables, allowing you to focus on creating an amazing application.

With practice and experience, you will become more comfortable with SQLite and be able to use its advanced features to build more complex and powerful Flutter applications. Remember, practice makes perfect!

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25831.4. Data Persistence with SQLite in Flutter: Data Insertion