React native realm
2020年1月13日
realm 数据库
https://realm.io/
https://realm.io/cn/docs/javascript/latest/
https://realm.io/cn/docs/objc/latest/#section
realm studio
image.png
数据迁移过程
import Realm from 'realm';
//数据库的定义
...
//数据迁移过程
var schemas = [
{
schema: [student],
schemaVersion: 1,
migration: (oldRealm, newRealm) => {
// only apply this change if upgrading to schemaVersion 1
if (oldRealm.schemaVersion < 1) {
const oldObjects = oldRealm.objects('student');
const newObjects = newRealm.objects('student');
// loop through all objects and set the name property in the new schema
for (let i = 0; i < oldObjects.length; i++) {
console.log('item start');
newObjects[i].studypattern = 0;
}
}
}
},
]
let nextSchemaIndex = Realm.schemaVersion(Realm.defaultPath);
console.log(Realm.defaultPath);
if (nextSchemaIndex != -1) {
while (nextSchemaIndex < schemas.length) {
// var migratedRealm = new Realm(schemas[nextSchemaIndex++]);
// migratedRealm.close();
const migratedRealm = new Realm({ ...schemas[nextSchemaIndex] });
nextSchemaIndex += 1;
migratedRealm.close();
}
}
export default new Realm({ schema: [person,student, teacher] ,schemaVersion: 1});
schemaVersion: number是表示数据库的版本的。
