This package helps your app to upgrade your app database schema in cleaned and incremental way.

Features

Use SQLiteSchema to bind onCreate and onUpgrade parameters in the openDatabase SQLite method. SQLiteSchema is in charge of upgrade the database schema up to date.

Getting started

It packages implements the Command design pattern.

1. SQLiteSchema: the invoker, it knows the commands to execute to upgrade the database schema.
2. CommandScript: the command. Create one concrete command for each new version of your database. If in your next build yo have to change your database schema, create a concrete command with the sql script and add it into the SQLiteSchema.
3. Receiver: Batch. We send the scripts to the Batch to upgrade the database schema.

Usage

Use SQLiteSchema to bind openDatabase parameters:

import '/src/config/enviroment.dart';
import '/src/data/sqlite/sqlite_scheme.dart';
import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';

/// It manages sqlite database connection.
class SQLiteDatabase {

  /// Initializes and returns sqlite database connection.
  Future<Database> initializeDB() async {

    ///gets database location.
    String path = Environment().config.getAppDocumentsPath();

    ///You must indicate what to do onCreate and what onUpdate
    ///and our SQLiteSchema is the one who is in charge of that.
    return openDatabase(
        join(path, 'myapp_database.db'),
        onCreate: (database, version) async {
          SQLiteSchema().create(database, version);
        },
        onUpgrade: (db, oldVersion, newVersion) async {
          SQLiteSchema().upgrade(db, oldVersion, newVersion);
        },
        version: Environment().config.appDatabaseVersion
    );
  }

}

Then you have to create Commands. For this example, I created two concrete commands:

• CommanScriptV1: it creates the first version of database schema. It creates the table “LogData”
• CommandScriptV2: it upgrades the database schema, it alters LogData table adding one more column.

import '/src/data/sqlite/command_script.dart';
import '/src/data/sqlite/sqlite_scheme.dart';

/**
 * Command to create the first version of the database.
 */
class CommandScriptV1 extends CommandScript{

  Future<void> execute(Batch batch) async {
    batch.execute("CREATE TABLE log_data (id INTEGER PRIMARY KEY AUTOINCREMENT,"
        " message TEXT NOT NULL, datetime INTEGER)");
    }

}

import '/src/data/sqlite/command_script.dart';
import '/src/data/sqlite/sqlite_scheme.dart';

/**
 * Command to update datbase schema to v2.
 */
class CommandScriptV2 extends CommandScript{

  Future<void> execute(Batch batch) async {
    batch.execute("ALTER TABLE log_data ADD level INTEGER");
  }
}

Then assign those commands to sqliteSchema indicating the version

SQLiteSchema sqliteSchema = SQLiteSchema();
sqliteSchema.setCommand(1, CommandScriptV1());
sqliteSchema.setCommand(2, CommandScriptV2());