I am currently trying to append data through I pull from Firebase to a table in the order of newest to oldest posts. I currently have the following setup in my code base (simplified to address issue):
var theDataRef = new Firebase('https://my-app.firebaseio.com');
theDataRef.orderByChild("timestamp").limitToLast(25).on('child_added', function (snapshot) {
var message = snapshot.val();
displaytableRow(message.name, message.text);
}
function displaytableRow(name, message) {
$("#sch").find('tbody > tr:first')
.before($("<tr><td><div>" + name + ":" + message + "</div></td></tr>"))
};
I have tried to create a table that displays newest to oldest data by using both firebase and jquery techniques but every time my data is displayed in a random order. I have a working timestamp field on every record in my data as well but even ordering by that does not solve the problem. Has anybody had any experience building this successfully?
EDIT:
The timestamp is gotten with the following code:
var timestamp = Firebase.ServerValue.TIMESTAMP;
And the database architecture is structured like so:
If you want to order your posts from newest to oldest you can do the following:
1/ Store a field in your post that is the inverse of the TimeStamp as follows:
var tDate = new Date().getTime();
var postData = {
//.....
timestampInverted: (0 - tDate),
//.....
};
2/ Query your posts ordered by this field as follows:
theDataRef.orderByChild("timestampInverted").limitToLast(25).once('value', function(snapshot) {
snapshot.forEach(function(childSnapshot) {
displaytableRow(childSnapshot.val().name, childSnapshot.val().text);
});
});
It is important to note that theDataRef.orderByChild("timestampInverted").limitToLast(25) returns a Query, which returns a DataSnapshot : Therefore you need to use snapshot.forEach() (see doc here) to iterate over the different posts items.
Also note that "even when there is only a single match for the query, the snapshot is still a list; it just contains a single item. To access the item, you always need to loop over the snapshot".
Related
I have some data in a directory and I want to retrieve the value of a certain object e.g. Get the value of "NVR".
Another task I need to do is have a 'for' loop to go over and get information about different questions from the following data. I would need to get the number e.g. "001" and the items inside of that subdirectory. And it would also need to go through every directory in 'questions' such as NVR or MTH.
For the first one, you can try this:
firebase.database().ref().child("unique").on('value', function(snapshot) {
var datas = snapshot.val();
var nvr=datas.NVR;
)};
For the second one try this:
firebase.database().ref().child("questions").child("NVR").on('value', function(snapshot) {
snapshot.forEach(function(child) {
var keys=child.key;
var datas = child.val();
var correcta=child.val().correctAnswer;
var num=child.val().numberOfAnswers;
//etc
});
});
the first one the snapshot will be at unique, then you will be able to retrieve the child NVR.
In the second one, you iterate inside NVR and retrieve the key using var keys=child.key;
Try something like this for going through every directory in questions and for each one getting all the questions in it :
firebase.database.ref('questions').on('value').then((snapshots) => {
//print whole questions group (nvr, mth, etc)
console.log(snapshots.val())
snapshots.forEach((snapshot) => {
//print each question in question group
console.log(snapshot.val())
})
}
Both Peter's and Egor's answers load all data under unique. Since you know the key of the item whose value you want to retrieve, you can load this more efficiently with:
firebase.database().ref("unique/NVR").on('value', function(snapshot) {
var nvr=snapshot.val();
)};
I've looking for an answer for like 5 five hours straight, hope somebody can help. I have a MongoDb collection results (I'm using mLab) which looks like this:
{
"user":"5818be9c74aaec1824c28626"
"results":[{
"game_id":14578,
"level1":-1,
"level2":-1,
"level3":-1
},
{ ....
}],
{ "user":....
}
}
"user" is a MongoID I save in a previous part of the code, "results" is a record of scores. When an user does a new score, I have to update the score of the corresponding level (I'm using NodeJS).
This is one of the things I've tried so far.
app.get('/levelCompleted/:id/:time', function (request, response) {
var id = request.params.id;
var time = parseInt(request.params.time);
var u= game.getUserById(id);
var k = "results.$.level"+(u.level);
//I build the key to update dinamycally
dbM.collection("results").update(
{user:id,
"results.game_id":u.game_id
//u has its own game_id
},
{$set: {k:time}}
);
...
response.send(...);
});
I've checked the content of every variable and parameter, tried also using $elemMatch and dot notation, set upsert and multi, with no results. I've used an identical command on mongo shell and it has work on the first try.
Update with Mongo Shell
If someone could tell me what I'm doing wrong or point me in the right direction, it would be great.
Thanks
When you use a MongoId as a field in a MongoDB, you can't just pass a string with the id to do the query, you have to identify that string as an ObjectId (Id type in Mongo). Just add a new require in your node.js file.
var ObjectID = require("mongodb").ObjectID;
And use the imported constructor in your update request.
dbM.collection("results").update(
{user:ObjectID(id),...
...
}
I found that Parse is now supported by the Buddy platform, but all the forum/help files from the old Parse website are gone...
What i would like to do is query for one row in a table by row number/index.
I now do this, but it seems inefficient to me to get all data and then select the row (although it works fine):
var thisRow = Parse.Object.extend(GlobTable);
var query= new Parse.Query(thisRow);
query.descending('updatedAt');
query.find({
success: function(results) {
var object = results[RowNumberThatINeed];
//etc using object
#Ran, thanks! Somehow it doesn't work, Parse will store '1' for every row: 1,1,1,1. But it saves all other data ok.
var Object = Parse.Object.extend(LocTable);
var obj = new Object();
obj.set("User", LocUser);
obj.set("Happened", d);
obj.set("Happy", b);
obj.set("Learned",a);
obj.set("ConnectedTo",c);
obj.increment("rowIndex");
obj.save({
success: function(obj) {
updateDatabase();
alert("Your data is saved");
},
error: function(obj, err) {
alert("Your data was not saved. Sorry..." + err);
}
});
you solution will work but you will experience a lot performance issues when your table will growth.
What i suggest to you is the following solution:
Add another field to your GlobTable of type integer. This field will be incremental field and will store your row index (let's call this field rowIndex)
Each time you save a new object to this table make sure you increment this field by using the following command:
object.increment("rowIndex");
Now your query should look like the following:
var thisRow = Parse.Object.extend(GlobTable);
var query= new Parse.Query(thisRow);
query.equalTo("rowIndex",RowNumberThatINeed);
query.first().then(function(result){
// do something with the result
},function(error){
// error handling
});
If you want event better performance you can create index (in MongoDb) on your rowIndex.
In my code snippets i use Promises according to the best practices.
I use first and not find because there will always be one object for this index
I am trying to figure out a way to fetch only the filtered values from a table if a filter is active in Office-JS API.
Right now the only way I have figured to fetch all the table data is from the table range values property:
var table = tables.getItemAt(0);
var tableRange = table.getRange();
tableRange.load("values");
ctx.sync().then(function () {
// This returns all the values from the table, and not only the visible data
var values = tableRange.values;
});
Any ideas on how I can proceed to fetch only the visible values from the table if a filter is active?
From previous experience with Office Interop I have achieved the same by looping through the different Areas of the table range, but I am unable to find the equivalent to Areas in Office-JS.
The upcoming next wave of features as part of Excel JS APIs 1.3 will include a new object "RangeView" that allows you to read only the visible values off the Range object.
Here's a link to the open spec on GitHub - https://github.com/OfficeDev/office-js-docs/tree/ExcelJs_1.3_OpenSpec/excel.
Note that this isn't available just yet, but will be in the near future.
Usage for your case off a table would look like this:
var table = tables.getItemAt(0);
var visibleView = table.getRange().getVisibleView();
ctx.load(visibleView);
ctx.sync().then(function () {
var values = visibleView.values;
});
One way to get only filtered data is through the Binding.getDataAsync method, which takes a filterType parameter.
Office.select("bindings#myTableBinding1").getDataAsync({
coercionType: "table",
filterType: "onlyVisible"
},function(asyncResult){
var values = (asyncResult.value.rows);
});
This code assumes you have already created a binding to the table. If not, you can run the following code first, which uses the table name to call Bindings.addFromNamedItemAsync:
Office.context.document.bindings.addFromNamedItemAsync("Table1","table",{
id: "myTableBinding1"
},function(asyncResult){
// handle errors and call code sample #1
});
Note that the solution above is supported as far back as Excel 2013 because it uses the shared APIs. The Excel-specific API set doesn't yet have the capability to return only unfiltered data.
-Michael Saunders, PM for Office add-ins
Currently, I have a table named Appointments- on appointments, I have a Relation of Clients.
In searching the parse documentation, I haven't found a ton of help on how to eagerly fetch all of the child collection of Clients when retrieving the Appointments. I have attempted a standard query, which looked like this:
var Appointment = Parse.Object.extend("Appointment");
var query = new Parse.Query(Appointment);
query.equalTo("User",Parse.User.current());
query.include('Rate'); // a pointer object
query.find().then(function(appointments){
let appointmentItems =[];
for(var i=0; i < appointments.length;i++){
var appt = appointments[i];
var clientRelation = appt.relation('Client');
clientRelation.query().find().then(function(clients){
appointmentItems.push(
{
objectId: appt.id,
startDate : appt.get("Start"),
endDate: appt.get("End"),
clients: clients, //should be a Parse object collection
rate : appt.get("Rate"),
type: appt.get("Type"),
notes : appt.get("Notes"),
scheduledDate: appt.get("ScheduledDate"),
confirmed:appt.get("Confirmed"),
parseAppointment:appt
}
);//add to appointmentitems
}); //query.find
}
});
This does not return a correct Clients collection-
I then switched over to attempt to do this in cloud code- as I was assuming the issue was on my side for whatever reason, I thought I'd create a function that did the same thing, only on their server to reduce the amount of network calls.
Here is what that function was defined as:
Parse.Cloud.define("GetAllAppointmentsWithClients",function(request,response){
var Appointment = Parse.Object.extend("Appointment");
var query = new Parse.Query(Appointment);
query.equalTo("User", request.user);
query.include('Rate');
query.find().then(function(appointments){
//for each appointment, get all client items
var apptItems = appointments.map(function(appointment){
var ClientRelation = appointment.get("Clients");
console.log(ClientRelation);
return {
objectId: appointment.id,
startDate : appointment.get("Start"),
endDate: appointment.get("End"),
clients: ClientRelation.query().find(),
rate : appointment.get("Rate"),
type: appointment.get("Type"),
notes : appointment.get("Notes"),
scheduledDate: appointment.get("ScheduledDate"),
confirmed:appointment.get("Confirmed"),
parseAppointment:appointment
};
});
console.log('apptItems Count is ' + apptItems.length);
response.success(apptItems);
})
});
and the resulting "Clients" returned look nothing like the actual object class:
clients: {_rejected: false, _rejectedCallbacks: [], _resolved: false, _resolvedCallbacks: []}
When I browse the data, I see the related objects just fine. The fact that Parse cannot eagerly fetch relational queries within the same call seems a bit odd coming from other data providers, but at this point I'd take the overhead of additional calls if the data was retrieved properly.
Any help would be beneficial, thank you.
Well, in your Cloud code example - ClientRelation.query().find() will return a Parse.Promise. So the output clients: {_rejected: false, _rejectedCallbacks: [], _resolved: false, _resolvedCallbacks: []} makes sense - that's what a promise looks like in console. The ClientRelation.query().find() will be an async call so your response.success(apptItems) is going to be happen before you're done anyway.
Your first example as far as I can see looks good though. What do you see as your clients response if you just output it like the following? Are you sure you're getting an array of Parse.Objects? Are you getting an empty []? (Meaning, do the objects with client relations you're querying actually have clients added?)
clientRelation.query().find().then(function(clients){
console.log(clients); // Check what you're actually getting here.
});
Also, one more helpful thing. Are you going to have more than 100 clients in any given appointment object? Parse.Relation is really meant for very large related collection of other objects. If you know that your appointments aren't going to have more than 100 (rule of thumb) related objects - a much easier way of doing this is to store your client objects in an Array within your Appointment objects.
With a Parse.Relation, you can't get around having to make that second query to get that related collection (client or cloud). But with a datatype Array you could do the following.
var query = new Parse.Query(Appointment);
query.equalTo("User", request.user);
query.include('Rate');
query.include('Clients'); // Assumes Client column is now an Array of Client Parse.Objects
query.find().then(function(appointments){
// You'll find Client Parse.Objects already nested and provided for you in the appointments.
console.log(appointments[0].get('Clients'));
});
I ended up solving this using "Promises in Series"
the final code looked something like this:
var Appointment = Parse.Object.extend("Appointment");
var query = new Parse.Query(Appointment);
query.equalTo("User",Parse.User.current());
query.include('Rate');
var appointmentItems = [];
query.find().then(function(appointments){
var promise = Parse.Promise.as();
_.each(appointments,function(appointment){
promise = promise.then(function(){
var clientRelation = appointment.relation('Clients');
return clientRelation.query().find().then(function(clients){
appointmentItems.push(
{
//...object details
}
);
})
});
});
return promise;
}).then(function(result){
// return/use appointmentItems with the sub-collection of clients that were fetched within the subquery.
});
You can apparently do this in parallel, but that was really not needed for me, as the query I'm using seems to return instantaniously. I got rid of the cloud code- as it didnt seem to provide any performance boost. I will say, the fact that you cannot debug cloud code seems truly limiting and I wasted a bit of time waiting for console.log statements to show themselves on the log of the cloud code panel- overall the Parse.Promise object was the key to getting this to work properly.