数据迁移

Data Migration

A library for applying a series of migrations to update old versions of data structures to the most recent one.

Installation

dependencies:
  data_migration:

How to use

1. Create your set of migration

   class CounterV1DataMigration implements DataMigration {
     const CounterV1DataMigration();
   
     @override
     int get fromVersion => 1;
   
     @override
     int get toVersion => 2;
   
     @override
     Future<dynamic> migrate(dynamic data) async {
       final counter = SimpleCounter(data as int);
       return counter.toJson();
     }
   }
   
   final migrator = DataMigrationManager(
     [
       CounterV1DataMigration(),
     ],
   );
   

2. Apply migration on data

     final migrated1 = await _migrator.migrateIfNeeded(
        3,
        fromVersion: 1,
     );
   

Examples

In the example and tests, there are some examples of "data migration."