sqflite_migrations 0.1.2

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sqflite_migrations #

Migrations manager for sqflite.

• Create migrations
• Run migrations
• Rollback migrations

Getting Started #

In your flutter project add the dependency:

dependencies:
  ...
  sqflite_migrations: ^0.1.0 

Usage example #

Import sqflite_migrations.dart

import 'package:sqflite_migrations/sqflite_migrations.dart';

Creating a migration #

Create a new instance of the Migration class you imported from the package.

Its attributes are:

• The migration's name, which should be unique.
• An up method that must return the query you want to run when the migration is run.
• A down method that returns the query you want to run when the migration is rolledback.

Example:

Migration createUsersTable = new Migration(
  'create-users-table',
  () => '''
    CREATE TABLE users( 
      id INT PRIMARY KEY,
      name TEXT NOT NULL
    );
  ''',
  () => 'DROP TABLE users;',
);

Running migrations #

You will run every migration in your list that was not ran already.

Assuming you want to run migrations only when your database is updated, you should run the runMigrations method on the onUpgrade method of sqflite.

It accepts as parameters:

• Your current db of type Database.
• An int with the new version.
• Your migrations list of type List<Migration>.

Example:

  onUpgrade(Database db, int previousVersion, int newVersion) {
    runMigrations(db, newVersion, migrations);
  }

And then you pass this method when you create the database:

 Database db = await openDatabase(path,
        version: _databaseVersion,
        onCreate: _onCreate,
        onUpgrade: onUpgrade);

Undoing migrations #

This functionality will undo every migrations that was implemented in a version above the current one.

Undoing migrations works the other way around of running migrations: you call the undoMigrations method in the method passed to the onDowngrade attribute.

It's parameters are:

• The current db of type Database.
• An int with the new version.
• Your migrations list of type List<Migration>.

Example:

  onDowngrade(Database db, int previousVersion, int newVersion) {
    undoMigrations(db, newVersion, migrations);
  }

In case you passed all the parameters the openDatabase function should look like this:

    Database db = await openDatabase(path,
        version: _databaseVersion,
        onCreate: _onCreate,
        onUpgrade: onUpgrade,
        onDowngrade: onDowngrade);