I've been creating a consumer who "grants" ids to clients when they perform certain tasks. It occurred to me at some point that it might be entirely superfluous to worry about the path before I do a .push().name() to create new ids.
Does it matter what path I run the .push().name() on to create a unique ID? Does Firebase generate the IDs entirely based on timestamp, without regard to the path the ID will be assigned to?
Currently, push() ids are generated based on timestamps (along with some randomness). The path on which the id is being pushed is not used as part of the id.
Related
In Microsoft Project, the only way to reset Unique IDs in the past was to change all Unique IDs in a file. This is rarely done but possible to do if someone happened to want the schedule to have Unique IDs in ascending order like the Task IDs. Recently, I was asked if it was now possible to set or change the Unique ID of a singular task. I don't believe that you can and I haven't found any documentation from Microsoft that says that this is possible. Does anyone know if you can in fact set or change the Unique ID of a single task?
No. Nothing has changed--the Unique ID is a calculated field which is another way of saying it's unchangeable by the user.
A very quick search leads to the documentation: Unique ID fields which states:
The Unique ID field contains the number that Microsoft Office Project automatically designates whenever a new task, resource, or assignment is created in the current project. This number indicates the sequence in which the task, resource, or assignment was created, regardless of placement in the schedule.
There are several categories of Unique ID fields.
Data Type Integer
Unique ID (task field)
Entry Type Calculated
How Calculated As you create new tasks, Project adds a unique number to each task in the project. This number is unique in that it is never rearranged or reused if the task is moved or deleted.
I read somewhere that db.collection("mycollection").document().getId(); gives document Id in mycollection without hitting cloudstore database. But how it is possible to create unique Id without knowing document id of already existing doucments or hitting couldstore?
The auto-ID that is generated when you call document() is a fairly basic UUID (universally unique identifier). Such identifier are statistically guaranteed to be unique. In my words: there is so much random information in there, that the chances of two calls generating the same value are infinitesimally small.
So Firestore doesn't actually call the server to check whether the ID it generates is unique. It instead relies on the mathematical properties of picking a single value out of a sufficiently large and random set to be very certain it is unique.
Whenever i will upload the data to the firebase it give random name to the child node. In the image "Upload" this name in given by me but what about inside name i want to change the name of inside the upload root how i can do that
The name inside the Upload is generated using push(), that you are using in your code, that is why you see it.
push() is a method that creates a random id to be able to seperate records in the database and also to be able to easily identify records in the Firebase Database.
push()
Create a reference to an auto-generated child location. The child key is generated client-side and incorporates an estimate of the server's time for sorting purposes. Locations generated on a single client will be sorted in the order that they are created, and will be sorted approximately in order across all clients.
more info here: https://firebase.google.com/docs/reference/android/com/google/firebase/database/DatabaseReference.html#push()
I'm trying to push new data into Firebase but it keeps generating an unique ID and an extra child node for me. How can I stop generating the ID and extra node or is there another way to push data into Firbase? My dataset is given and I just need to dump the dataset into the db. (But I'm slowly updating this given dataset.)
Firease always generates the unique id when using the push method. You can use it as a key or as a parent node. This post describes push in more detail.
https://firebase.googleblog.com/2015/02/the-2120-ways-to-ensure-unique_68.html
You should use set to publish new data to firebase if push doesn't fit your use case. There is also an update method as set will overwrite any data in the given path.
https://firebase.google.com/docs/database/web/save-data
I generally use set for new data, or if I change how I have my data structured, or if I am appending new data in a path, update to make changes to fields for a dataset, and push for sets of data that I want organized in a list by time( i.e. Chat message log ).
In Firebase if I'd like to create a child node with a unique ID it appears I have two options:
Push() :
Use the push() method to append data to a list in multiuser
applications. The push() method generates a unique ID every time a new
child is added to the specified Firebase reference. By using these
auto-generated keys for each new element in the list, several clients
can add children to the same location at the same time without write
conflicts. The unique ID generated by push() is based on a timestamp,
so list items are automatically ordered chronologically.
childByAutoId:
childByAutoId generates a new child location using a unique key and
returns a FIRDatabaseReference to it. This is useful when the children
of a Firebase Database location represent a list of items. The unique
key generated by childByAutoId: is prefixed with a client-generated
timestamp so that the resulting list will be chronologically-sorted.
Whats the difference?
Nevermind, it appears they are the same except they cater to different platforms:
Save Data on IOS
childByAutoId : Add to a list of data. Every time you call childByAutoId, Firebase generates a unique ID, such as user-posts/<user-id>/<unique-post-id>.
Save Data on Web
push() : Add to a list of data. Every time you call push(), Firebase generates a unique ID, such as user-posts/<user-id>/<unique-post-id>.