Realm 在 ReactNative 中插入新模式

Question

const schema1 = [
    rolesSchema,
    userMutedInRoomSchema,
    uploadsSchema,
    usersForMentionSchema,
    contactsSchema,
];
const schema2 = [
    rolesSchema,
    userMutedInRoomSchema,
    uploadsSchema,
    usersForMentionSchema,
    contactsSchema,
    stickersPackagesSchema,
    stickersCollectionSchema
];

以上是两个模式 Schema1 是我已经使用的模式，它工作正常 Schema2 是新架构，其中我在联系人架构之后的末尾添加了新表（架构）。我已经遵循了文档，但我找不到任何解释在旧架构中添加新表的内容。下面是我用来初始化在运行时崩溃的新架构的代码

const path = database.replace(/(^w+:|^)///, '');
        return this.databases.activeDB = new Realm({
            path: `${ path }Value.realm`,
            schema:schema2,
            schemaVersion:1,
            migration: (oldRealm, newRealm) => {

            },
        });

Answer 1

如果要更新生产应用的架构。然后，您需要编写迁移逻辑并更新架构版本。

Realm.open({
  schema: [PersonSchema],
  schemaVersion: 1,
  migration: (oldRealm, newRealm) => {
    // only apply this change if upgrading to schemaVersion 1
    if (oldRealm.schemaVersion < 1) {
      const oldObjects = oldRealm.objects('Person');
      const newObjects = newRealm.objects('Person');
      // loop through all objects and set the name property in the new schema
      for (let i = 0; i < oldObjects.length; i++) {
        newObjects[i].name = oldObjects[i].firstName + ' ' + oldObjects[i].lastName;
      }
    }
  }
}).then(realm => {
  const fullName = realm.objects('Person')[0].name;
});

参考： https://realm.io/docs/javascript/latest/#performing-a-migration

如果您当前正在开发应用程序，则只需更新 schemaVersion 并添加 deleteRealmIfMigrationNeeded 属性即可删除旧的过时数据

参考： https://realm.io/docs/javascript/latest/#opening-realms