我最初犯了一个错误，忘记在用户注册时初始化我的数组字段（设计），因此在我的 Parse 仪表板中，行显示为
(undefined)[]var query = new Parse.Query("User");
query.equalTo("designs", "(undefined)");
query.each(function(obj) {
obj.set("designs", "[]");
return obj.save();
}).then(function() {
// All objects updated.
}, function(err) {
console.log(err);
});
我认为
(undefined)更新：第二次尝试。是不是越来越近了？
private void updateAllRows(final int skip) {
ParseQuery<ParseUser> query = ParseUser.getQuery();
query.setLimit(500);
query.setSkip(skip);
query.whereDoesNotExist("designs");
query.findInBackground(new FindCallback<ParseUser>() {
@Override
public void done(List<ParseUser> results, ParseException e) {
if (results.size() > 0) {
// The query was successful.
for (int i = 0; i < results.size(); i++) {
ParseUser user = results.get(i);
String[] designs = new String[0];
user.put("designs", Arrays.asList(designs));
try {
ParseUser.saveAll(results);
if (results.size() >= 500) {
updateAllRows(skip + 500); // make a recursion call with different skip value
}
} catch (ParseException e1) {
e1.printStackTrace();
}
}
Log.d(getClass().toString(), ": The batch job was successfully completed.");
} else {
// The query was unsuccessful.
Log.d(getClass().toString(), ": The batch job was not successful.");
}
}
});
}
我使用类的 onCreate 方法中的以下内容调用上述函数：
int skip = 0;
updateAllRows(skip);
这是在不使用云代码的情况下解决此问题的最佳方法吗？
错误：
08-08 12:38:43.034 24003-24053/? E/HttpOperation: [luq{checkandengageuser, getmobileexperiments}] Unexpected exception
java.io.IOException: 1 of 2 operations in the batch failed
at luj.a(PG:268)
at lth.o(PG:10642)
at ltc.a(PG:1402)
at lth.i(PG:154)
at ly.f(PG:51849)
at dsr.a(PG:1255)
at dsr.a(PG:20077)
at dsr.a(PG:706)
at dss.run(PG:1548)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:423)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
JavaScript 版本 1. 您可以使用 Parse.Object.saveAll 在一次服务调用中保存多个对象 2. 您必须使用 limit 和 skip 才能一次处理 500 个（或更少）个项目。 3. 您需要使用 query.doesNotExist("designs"); 才能获取 design 列中包含 undefined 的所有项目
function updateAllRows(skip) {
var query = new Parse.Query(Parse.User);
query.limit(500);
query.skip(skip);
// get recors where designs is not exist or is undefined
query.doesNotExist("designs");
query.find().then(function(results) {
// if we got results then change the designs property
if (results.length > 0) {
for (var i = 0; i < results.length; i++) {
var item = results[i];
item.set("designs", []);
}
Parse.Object.saveAll(results).then(function() {
// if we got 500 or more results then we know
// that we have more results
// otherwise we finish
if (results.length >= 500) {
updateAllRows(skip + 500); // make a recursion call with different skip value
}
}, function(err) {
// error occured
});
}
}, function(error) {
// error occured while trying to fetch data
});
};Android Java版本
private void updateAllRows(final int skip){
ParseQuery<ParseUser> query = ParseUser.getQuery();
query.setLimit(500);
query.setSkip(skip);
query.whereDoesNotExist("designs");
query.findInBackground(new FindCallback<ParseUser>() {
@Override
public void done(final List<ParseUser> users, ParseException e) {
if (e == null){
for (ParseUser user : users){
user.put("designs",new ArrayList<>());
}
// save all objects in one server call
ParseObject.saveAllInBackground(users, new SaveCallback() {
@Override
public void done(ParseException e) {
if (e == null){
if (users.size() >= 500){
updateAllRows(skip + 500);
}
} else {
// error while saving objects
}
}
});
}
}
});
}
}
顺便说一句！您还可以在云代码中创建云函数并从客户端触发该函数
Javascript版本：
async updateAllRows(skip) {
const query = new Parse.Query(Question);
query.limit(500);
query.skip(skip);
query.doesNotExist("update");
try {
const results = await query.find();
for (const result of results) {
result.set('update', 'your update')
}
await Parse.Object.saveAll(results)
if (results.length >= 500){
updateAllRows(skip + 500).then().catch();
}
} catch (e) {
}
}
我只是纠正了上面的答案，参数跳过保持在 0，因为数据已更新
function updateAllRows(skip) {
var query = new Parse.Query(Parse.User);
query.limit(500);
query.skip(skip);
// get recors where designs is not exist or is undefined
query.doesNotExist("designs");
query.find().then(function(results) {
// if we got results then change the designs property
if (results.length > 0) {
for (var i = 0; i < results.length; i++) {
var item = results[i];
item.set("designs", []);
}
Parse.Object.saveAll(results).then(function() {
// if we got 500 or more results then we know
// that we have more results
// otherwise we finish
if (results.length >= 500) {
updateAllRows(skip); // make a recursion call with different skip value
}
}, function(err) {
// error occured
});
}
}, function(error) {
// error occured while trying to fetch data
});
};
模拟，有3850条数据可供更新
0 ->测试 1000 0 ->测试 1000 0 ->测试 1000 0 ->测试 850