On my process, I have a variable that is an array of objects similar to the following:
"llista-finques" : [
{
"FIN_ID": "H10",
"FIN_NOMBRE": "PLUTO VIVIENDAS",
"FIN_PROPIETARIO": "H10",
"FIN_LINIA_NEGOCIO": "Horizontal"
},
{
"FIN_ID": "H11",
"FIN_NOMBRE": "PLUTO PARKING",
"FIN_PROPIETARIO": "H11",
"FIN_LINIA_NEGOCIO": "Horizontal"
},
{
"FIN_ID": "H12",
"FIN_NOMBRE": "PINTO VIVENDES",
"FIN_PROPIETARIO": "H12",
"FIN_LINIA_NEGOCIO": "Horizontal"
},
{
"FIN_ID": "H16",
"FIN_NOMBRE": "ZURUBANDO",
"FIN_PROPIETARIO": "H16",
"FIN_LINIA_NEGOCIO": "Horizontal"
} ......
I am trying to create a Calculated Propery in one of my forms that needs to create a subset of this array filtering by object property. In order to do so, I was hoping to use the following javascript for the calculated field:
return this.llista-finques.filter(finca => {return finca.FIN_PROPIETARIO === this.Id_client});
For some reason this code produces no result, and after many tests, I have arrived at the conclussion that the variable "this.llista-finques" is simply not accessible from the script, although it is available in the process data.
If I change the Calculated Property script to simply return the value of the variable as bellow:
return this.llista-finques;
or even someting that simply should return a string:
return this.llista-finques[0].FIN_ID
the calculated property produces no result.
If I do exaclty the same with any of the other process variables that are not arrays of objects the calculated property seems to work correctly.
Al the testing I have done is using the screen preview debuging tools of Processmaker 4.
Is there a limitation on the kind of variables I can use for calculated properties? Is this a processmaker bug?
This is embarassing ... after testing and testing and testing I figured out that the problem was due to the name of the variable I was using. Can't use a name with the character '-' ....
Once I corrected the variable name it all worked as expected.
Here's how I want my data tree to look in Firebase:
users:
--Travis:
------travisData:
--Stephanie:
------stephanieData:
My problem is that I can't seem to name a child using user input from a textfield.
Here's the code I have so far:
ref = Database.database().reference()
let username = String(emailTextField.text!)
//ref.child("users").setValue(["username": username])
ref.child("users").setValue(["\(username)": calendar])
The commented out line creates a child named "username" with the textfield.text as its content. But how can I create a child whose name is the textfield.text, with other data as its content? I've tried multiple combinations of using .child and .setValue, but everything keeps throwing me an error when I try to use the username variable instead of a plain string.
Here's the error I get:
Your problem is that Firebase doesn't accept the "." symbol in their user names. You would get the same problem even if you typed a string of letters with a "." such as "adfojnajsdnfjs.fjknasd" instead of "username".
I think you're looking for:
ref.child("users").child(username).setValue(calendar)
Although that depends on the value of calendar.
At the very least this should work:
ref.child("users").child(username).setValue(true)
And give you the following JSON:
"users": {
"Travis": true
}
To write a more complex structure, you can for example do:
ref.child("users").child(username).child("name").setValue(username)
Which results in:
"users": {
"Travis": {
name: "Travis"
}
}
As your require, I think this code will help you
ref.child("users").child("\(inputUsername)").updateChildValues(["travidDataKey": userData])
And
result image
users:
Travid2:
travidDataKey:"Travid Data"
I'm trying to test out Firebase to allow users to post comments using push. I want to display the data I retrieve with the following;
fbl.child('sell').limit(20).on("value", function(fbdata) {
// handle data display here
}
The problem is the data is returned in order of oldest to newest - I want it in reversed order. Can Firebase do this?
Since this answer was written, Firebase has added a feature that allows ordering by any child or by value. So there are now four ways to order data: by key, by value, by priority, or by the value of any named child. See this blog post that introduces the new ordering capabilities.
The basic approaches remain the same though:
1. Add a child property with the inverted timestamp and then order on that.
2. Read the children in ascending order and then invert them on the client.
Firebase supports retrieving child nodes of a collection in two ways:
by name
by priority
What you're getting now is by name, which happens to be chronological. That's no coincidence btw: when you push an item into a collection, the name is generated to ensure the children are ordered in this way. To quote the Firebase documentation for push:
The unique name generated by push() is prefixed with a client-generated timestamp so that the resulting list will be chronologically-sorted.
The Firebase guide on ordered data has this to say on the topic:
How Data is Ordered
By default, children at a Firebase node are sorted lexicographically by name. Using push() can generate child names that naturally sort chronologically, but many applications require their data to be sorted in other ways. Firebase lets developers specify the ordering of items in a list by specifying a custom priority for each item.
The simplest way to get the behavior you want is to also specify an always-decreasing priority when you add the item:
var ref = new Firebase('https://your.firebaseio.com/sell');
var item = ref.push();
item.setWithPriority(yourObject, 0 - Date.now());
Update
You'll also have to retrieve the children differently:
fbl.child('sell').startAt().limitToLast(20).on('child_added', function(fbdata) {
console.log(fbdata.exportVal());
})
In my test using on('child_added' ensures that the last few children added are returned in reverse chronological order. Using on('value' on the other hand, returns them in the order of their name.
Be sure to read the section "Reading ordered data", which explains the usage of the child_* events to retrieve (ordered) children.
A bin to demonstrate this: http://jsbin.com/nonawe/3/watch?js,console
Since firebase 2.0.x you can use limitLast() to achieve that:
fbl.child('sell').orderByValue().limitLast(20).on("value", function(fbdataSnapshot) {
// fbdataSnapshot is returned in the ascending order
// you will still need to order these 20 items in
// in a descending order
}
Here's a link to the announcement: More querying capabilities in Firebase
To augment Frank's answer, it's also possible to grab the most recent records--even if you haven't bothered to order them using priorities--by simply using endAt().limit(x) like this demo:
var fb = new Firebase(URL);
// listen for all changes and update
fb.endAt().limit(100).on('value', update);
// print the output of our array
function update(snap) {
var list = [];
snap.forEach(function(ss) {
var data = ss.val();
data['.priority'] = ss.getPriority();
data['.name'] = ss.name();
list.unshift(data);
});
// print/process the results...
}
Note that this is quite performant even up to perhaps a thousand records (assuming the payloads are small). For more robust usages, Frank's answer is authoritative and much more scalable.
This brute force can also be optimized to work with bigger data or more records by doing things like monitoring child_added/child_removed/child_moved events in lieu of value, and using a debounce to apply DOM updates in bulk instead of individually.
DOM updates, naturally, are a stinker regardless of the approach, once you get into the hundreds of elements, so the debounce approach (or a React.js solution, which is essentially an uber debounce) is a great tool to have.
There is really no way but seems we have the recyclerview we can have this
query=mCommentsReference.orderByChild("date_added");
query.keepSynced(true);
// Initialize Views
mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
mManager = new LinearLayoutManager(getContext());
// mManager.setReverseLayout(false);
mManager.setReverseLayout(true);
mManager.setStackFromEnd(true);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(mManager);
I have a date variable (long) and wanted to keep the newest items on top of the list. So what I did was:
Add a new long field 'dateInverse'
Add a new method called 'getDateInverse', which just returns: Long.MAX_VALUE - date;
Create my query with: .orderByChild("dateInverse")
Presto! :p
You are searching limitTolast(Int x) .This will give you the last "x" higher elements of your database (they are in ascending order) but they are the "x" higher elements
if you got in your database {10,300,150,240,2,24,220}
this method:
myFirebaseRef.orderByChild("highScore").limitToLast(4)
will retrive you : {150,220,240,300}
In Android there is a way to actually reverse the data in an Arraylist of objects through the Adapter. In my case I could not use the LayoutManager to reverse the results in descending order since I was using a horizontal Recyclerview to display the data. Setting the following parameters to the recyclerview messed up my UI experience:
llManager.setReverseLayout(true);
llManager.setStackFromEnd(true);
The only working way I found around this was through the BindViewHolder method of the RecyclerView adapter:
#Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
final SuperPost superPost = superList.get(getItemCount() - position - 1);
}
Hope this answer will help all the devs out there who are struggling with this issue in Firebase.
Firebase: How to display a thread of items in reverse order with a limit for each request and an indicator for a "load more" button.
This will get the last 10 items of the list
FBRef.child("childName")
.limitToLast(loadMoreLimit) // loadMoreLimit = 10 for example
This will get the last 10 items. Grab the id of the last record in the list and save for the load more functionality. Next, convert the collection of objects into and an array and do a list.reverse().
LOAD MORE Functionality: The next call will do two things, it will get the next sequence of list items based on the reference id from the first request and give you an indicator if you need to display the "load more" button.
this.FBRef
.child("childName")
.endAt(null, lastThreadId) // Get this from the previous step
.limitToLast(loadMoreLimit+2)
You will need to strip the first and last item of this object collection. The first item is the reference to get this list. The last item is an indicator for the show more button.
I have a bunch of other logic that will keep everything clean. You will need to add this code only for the load more functionality.
list = snapObjectAsArray; // The list is an array from snapObject
lastItemId = key; // get the first key of the list
if (list.length < loadMoreLimit+1) {
lastItemId = false;
}
if (list.length > loadMoreLimit+1) {
list.pop();
}
if (list.length > loadMoreLimit) {
list.shift();
}
// Return the list.reverse() and lastItemId
// If lastItemId is an ID, it will be used for the next reference and a flag to show the "load more" button.
}
I'm using ReactFire for easy Firebase integration.
Basically, it helps me storing the datas into the component state, as an array. Then, all I have to use is the reverse() function (read more)
Here is how I achieve this :
import React, { Component, PropTypes } from 'react';
import ReactMixin from 'react-mixin';
import ReactFireMixin from 'reactfire';
import Firebase from '../../../utils/firebaseUtils'; // Firebase.initializeApp(config);
#ReactMixin.decorate(ReactFireMixin)
export default class Add extends Component {
constructor(args) {
super(args);
this.state = {
articles: []
};
}
componentWillMount() {
let ref = Firebase.database().ref('articles').orderByChild('insertDate').limitToLast(10);
this.bindAsArray(ref, 'articles'); // bind retrieved data to this.state.articles
}
render() {
return (
<div>
{
this.state.articles.reverse().map(function(article) {
return <div>{article.title}</div>
})
}
</div>
);
}
}
There is a better way. You should order by negative server timestamp. How to get negative server timestamp even offline? There is an hidden field which helps. Related snippet from documentation:
var offsetRef = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com/.info/serverTimeOffset");
offsetRef.on("value", function(snap) {
var offset = snap.val();
var estimatedServerTimeMs = new Date().getTime() + offset;
});
To add to Dave Vávra's answer, I use a negative timestamp as my sort_key like so
Setting
const timestamp = new Date().getTime();
const data = {
name: 'John Doe',
city: 'New York',
sort_key: timestamp * -1 // Gets the negative value of the timestamp
}
Getting
const ref = firebase.database().ref('business-images').child(id);
const query = ref.orderByChild('sort_key');
return $firebaseArray(query); // AngularFire function
This fetches all objects from newest to oldest. You can also $indexOn the sortKey to make it run even faster
I had this problem too, I found a very simple solution to this that doesn't involved manipulating the data in anyway. If you are rending the result to the DOM, in a list of some sort. You can use flexbox and setup a class to reverse the elements in their container.
.reverse {
display: flex;
flex-direction: column-reverse;
}
myarray.reverse(); or this.myitems = items.map(item => item).reverse();
I did this by prepend.
query.orderByChild('sell').limitToLast(4).on("value", function(snapshot){
snapshot.forEach(function (childSnapshot) {
// PREPEND
});
});
Someone has pointed out that there are 2 ways to do this:
Manipulate the data client-side
Make a query that will order the data
The easiest way that I have found to do this is to use option 1, but through a LinkedList. I just append each of the objects to the front of the stack. It is flexible enough to still allow the list to be used in a ListView or RecyclerView. This way even though they come in order oldest to newest, you can still view, or retrieve, newest to oldest.
You can add a column named orderColumn where you save time as
Long refrenceTime = "large future time";
Long currentTime = "currentTime";
Long order = refrenceTime - currentTime;
now save Long order in column named orderColumn and when you retrieve data
as orderBy(orderColumn) you will get what you need.
just use reverse() on the array , suppose if you are storing the values to an array items[] then do a this.items.reverse()
ref.subscribe(snapshots => {
this.loading.dismiss();
this.items = [];
snapshots.forEach(snapshot => {
this.items.push(snapshot);
});
**this.items.reverse();**
},
For me it was limitToLast that worked. I also found out that limitLast is NOT a function:)
const query = messagesRef.orderBy('createdAt', 'asc').limitToLast(25);
The above is what worked for me.
PRINT in reverse order
Let's think outside the box... If your information will be printed directly into user's screen (without any content that needs to be modified in a consecutive order, like a sum or something), simply print from bottom to top.
So, instead of inserting each new block of content to the end of the print space (A += B), add that block to the beginning (A = B+A).
If you'll include the elements as a consecutive ordered list, the DOM can put the numbers for you if you insert each element as a List Item (<li>) inside an Ordered Lists (<ol>).
This way you save space from your database, avoiding unnecesary reversed data.
I have a question about the query based on the predefined constraints in PopotoJs. In this example, the graph can be filtered based on the constraints defined in the search boxes. The sample file in this example visualizations folder, constraint is only defined for "Person" node. It is specified in the sample html file like the following:
"Person": {
"returnAttributes": ["name", "born"],
"constraintAttribute": "name",
// Return a predefined constraint that can be edited in the page.
"getPredefinedConstraints": function (node) {
return personPredefinedConstraints;
},
....
In my graph I would like to apply that query function for more than one node. For example I have 2 nodes: Contact (has "name" attribute) and Delivery (has "address" attribute)
I succeeded it by defining two functions for each nodes. However, I also had to put two search box forms with different input id (like constraint1 and constraint2). And I had to make the queries in the associated search boxes.
Is there a way to make queries which are defined for multiple nodes in one search box? For example searching Contact-name and/or Delivery-adress in the same search box?
Thanks
First I’d like to specify that the predefined constraints feature is still experimental (but fully functional) and doesn’t have any documentation yet.
It is intended to be used in configuration to filter data displayed in nodes and in the example the use of search boxes is just to show dynamically how it works.
A common use of this feature would be to add the list of predefined constraint you want in the configuration for every node types.
Let's take an example:
With the following configuration example the graph will be filtered to show only Person nodes having "born" attribute and only Movie nodes with title in the provided list:
"Person": {
"getPredefinedConstraints": function (node) {
return ["has($identifier.born)"];
},
...
}
"Movie": {
"getPredefinedConstraints": function (node) {
return ["$identifier.title IN [\"The Matrix\", \"The Matrix Reloaded\", \"The Matrix Revolutions\"]"];
},
...
}
The $identifier variable is then replaced during query generation with the corresponding node identifier. In this case the generated query would look like this:
MATCH (person:`Person`) WHERE has(person.born) RETURN person
In your case if I understood your question correctly you are trying to use this feature to implement a search box to filter the data. I'm still working on that feature but it won't be available soon :(
This is a workaround but maybe it could work in your use case, you could keep the search box value in a variable:
var value = d3.select("#constraint")[0][0].value;
inputValue = value;
Then use it in the predefined constraint of all the nodes type you want.
In this example Person will be filtered based on the name attribute and Movie on title:
"Person": {
"getPredefinedConstraints": function (node) {
if (inputValue) {
return ["$identifier.name =~ '(?i).*" + inputValue + ".*'"];
} else {
return [];
}
},
...
}
"Movie": {
"getPredefinedConstraints": function (node) {
if (inputValue) {
return ["$identifier.title =~ '(?i).*" + inputValue + ".*'"];
} else {
return [];
}
},
...
}
Everything is in the HTML page of this example so you can view the full source directly on the page.
#Popoto, thanks for the descriptive reply. I tried your suggestion and it worked pretty much well. With the actual codes, when I make a query it was showing only the queried node and make the other node amount zero. I wanted to make a query which queries only the related node while the number of other nodes are still same.
I tried a temporary solution for my problem. What I did is:
Export the all the node data to JSON file, search my query constraint in the exported JSONs, if the file is existing in JSON, then run the query in the related node; and if not, do nothing.
With that way, of course I needed to define many functions with different variable names (as much as the node amount). Anyhow, it is not a propoer way, bu it worked for now.
I am trying to import a ms-excel 2007 sheet using excel-import plugin. It was simple to integrate with my project and I found it working as expected until I noticed that the number values in the cells are populated as real numbers with exponent.
For example if the cell contains value 9062831150099 -(populated as)->9.062831150099E12 i.e.
A |
_____________________
Registration Number |
____________________
9062831150099
Is populated as: [RegNum:9.062831150099E12]
Anyone could suggest me how I can change this representation back to its original format keeping its type as number?
Missed it at the first attempt but I figured out how to to achieve it:
When invoking the key methods (the ones that process cellMap and columnMaps) for example List bookParamsList = excelImportService.columns(workbook, CONFIG_BOOK_COLUMN_MAP) or Map bookParams = excelImportService.cells(workbook, CONFIG_BOOK_CELL_MAP )
There is also ability to pass in configuration information, i.e. to specify what to do if a cell is empty (i.e. to provide a default value), to make sure a cell is of expected type, etc.
So in my case I created a configuration parameter Map of properties of the object and passed it to the above methods. i.e.
Class UploadExcelDataController {
def excelImportService
static Map CONFIG_BOOK_COLUMN_MAP = [
sheet:'Sheet1',
startRow: 2,
columnMap: [
'A':'registrationNumber',
'B':'title',
'C':'author',
'D':'numSold',
]
]
static Map configBookPropertyMap = [
registrationNumber: ([expectedType: ExpectedPropertyType.IntType, defaultValue:0])
]
def uploadFile(){
...
List bookParamsList = excelImportService.columns(workbook, CONFIG_BOOK_COLUMN_MAP,configBookPropertyMap )
...
}
}