// Inside your [AppDelegate didFinishLaunchingWithOptions:]
// Notice setSchemaVersion is set to 1, this is always set manually. It must be
// higher than the previous version (oldSchemaVersion) or an RLMException is thrown
[RLMRealm setSchemaVersion:1
forRealmAtPath:[RLMRealm defaultRealmPath]
withMigrationBlock:^(RLMMigration *migration, NSUInteger oldSchemaVersion) {
// We haven’t migrated anything yet, so oldSchemaVersion == 0
if (oldSchemaVersion < 1) {
// Nothing to do!
// Realm will automatically detect new properties and removed properties
// And will update the schema on disk automatically
}
}];
// now that we have called `setSchemaVersion:withMigrationBlock:`, opening an outdated
// Realm will automatically perform the migration and opening the Realm will succeed
[RLMRealm defaultRealm];
1 回答
大卫说的是对的 . 如果确保正确执行迁移,则Realm可以轻松处理已删除和添加的属性 . 除非您实际上仍然需要
percentageOn
中的值,否则您甚至可以将迁移块留空,就像Realm网站上的示例一样: