Realm - 在迁移块中从Realm数据库删除对象

Question

我需要在迁移过程中从域中删除对象。

我有一个包含以下内容的AccountManager：

func logOut() {
    let realm = try! Realm()
    try! realm.write {
        realm.delete(realm.objects(Account.self))
        realm.delete(realm.objects(Address.self))
        ... // Other deletions
    }
}

但是每当我在迁移块中使用logOut()函数时，它总是失败。

    let config = Realm.Configuration(
        schemaVersion: 11,
        migrationBlock: { migration, oldSchemaVersion in
            if (oldSchemaVersion < 11) {
                // Delete objects from realm
                AccountManager().logOut() // DOESN'T WORK
            }
    })

    Realm.Configuration.defaultConfiguration = config

我绝对需要用户在此更新后重新登录 - 有没有办法在迁移块中执行这些删除操作？

- nth

Answer 1

你可以使用Migration.deleteData(forType typeName: String)来替代Realm.delete(_:)，方法如下。

Realm.Configuration(schemaVersion: 11, migrationBlock: { migration, oldSchemaVersion in
    if oldSchemaVersion < 11
        migration.deleteData(forType: Account.className)
        migration.deleteData(forType: Address.className)
        ...

- kishikawa katsumi

---

嗨，请查看我的关于 Realm 迁移的问题，链接为 https://stackoverflow.com/questions/59855380/how-can-i-replace-a-listobjects-with-object-field-in-realm - milad salimi

Answer 2

你可以告诉 Realm 在需要迁移时进行删除。

Realm.Configuration.defaultConfiguration = Realm.Configuration(
    schemaVersion: 10,
    migrationBlock: { migration, oldSchemaVersion in


    },
    deleteRealmIfMigrationNeeded: true
)

- wint

---

我能否指定仅在从版本10迁移到11时应用该领域删除？ - nth

我从未尝试过那个，我猜你必须编写自己的迁移代码。查看这个答案https://dev59.com/_5zha4cB1Zd3GeqPAiaI#40467810 - wint

仅在从特定版本迁移时删除realm，请查看https://github.com/realm/realm-js/issues/502#issuecomment-228058951 - haart