How to merge streams in flutter? - dart

I'm trying to query 2 collections from firebase and put it in a streambuilder.
There are lot of questions like this,but a lot of them are unsolved,or I just didn't really found the right one.
So,I got a users,and a salons collection in Firebase.
user1 contains his name,age,etc and he have another collection called favsalons. In salons are the description of salons like name,owner,etc
In app I want to list out the favsalons with their datas.
In SQL it would look something like this : Select salons.name,salons.owner From salons,user Where userID=user1 and favsalonsID=salonsID
Since I'm new to flutter,and to the non SQL databases,I got no clue how to do it.
Is there a simple solution?

You can't... You need to modify the structure of your data.
Watch the firebase team explanation.

Solved with simply nesting two streambuilders.

Related

How do I use importXML/importHTML to retrieve a stock options chain that is hidden?

I am trying to use importXML or importHTML function to retrieve a stock options chain, specifically using this function to get a table. So far, this is what I have:
=importhtml("https://bigcharts.marketwatch.com/quickchart/options.asp?symb=TSLA","table",3)
The problem I'm getting is that I can't retrieve "hidden" tables. For example, if you go on the website: https://bigcharts.marketwatch.com/quickchart/options.asp?symb=TSLA
If you scroll down on this page the hidden tables would only be revealed if you click on ,"show april 2022", "show may 2022", etc. I am trying to retrieve all of this information.
The end result is that I would like to create a table that looks like this:
https://www.barchart.com/stocks/quotes/tsla/put-call-ratios
And a table that looks like this:
https://www.barchart.com/stocks/quotes/TSLA/options?moneyness=10&view=stacked&expiration=2022-04-14-m
As a result, there are two things that I am trying to create, the above tables shown on barchart.
I have tried to use importHTML or importXML on barchart, but it looks like it's not allowed. If there is a way to directly retrieve the information from barchart, that would be a much better solution rather than having to import all of the data separately using a different website.
Please note, that I do have a beginner knowledge, so a step-by-step solution on what to do would be very helpful. Thank you

How can I store comments for a post using Parse & Swift?

I'm honestly stumped as to how I could do this. I've been searching and trying out different methods for the past day or so and none have worked. What I'm basically trying to do is store comments for a post (Each row represents a post). I've been reading through the Parse documentation and have tried to implement some of the things that they have there into my code in order to achieve this, but that hasn't worked out either. If anybody could help me out, I'd be extremely greatful.
This exact task is the example provided in the documentation.
http://docs.parseplatform.org/ios/guide/#relational-data
You need to create a new class called "Comments" and then refrence its parent post as one of it's columns.

Delete rows in CloudBoost using conditions

Is there a quick way to delete rows in a CloudBoost database without sending an ID as parameter?
For example, imagine that I have a list of Dogs and would like to delete those whose color is white.
Looking in the documentation, I could create a CloudQuery to retrieve all Dogs that matches this condition and then call CloudObject.deleteAll to remove all of them. The problem in this solution is that I needed to retrieve all the data to be able to remove them.
Is there any straightforward solution for this problem to avoid making unnecessary requests to the server?
currently, cloudboost has no option like this that you are looking for. To delete you have to first fetch cloudobjects then deleteall(). Anyway, you can contact cloudboost team and request for this feature. I am sure they will help you out on this.

How to delete a column in Parse.com using Swift

How do I delete a column in Parse using Swift? I am new to Parse. I have looked at the Parse documentation, but could not figure it. After trying many variations of the docs in my code nothing has worked. If it is not possible to delete a column, then how do I delete a row.
In your example code, QuestionsandAnswers is an object, not a class.
If you really intend to delete a class, that is now possible with the Schema API that the Parse team just released: http://blog.parse.com/announcements/releasing-the-schema-api/
Here is the specific documentation for removing a class which you can do with cURL or Python: https://parse.com/docs/rest/guide#schemas
Good luck (and be careful). :)

Meteor publish-with-relations VS collection-helpers for joins?

What's the best way to do joins in Meteor/mongo? Use one of these packages, or something else:
publish-with-relations
https://github.com/erundook/meteor-publish-with-relations/blob/master/publish_with_relations.coffee
collection-helpers
https://github.com/dburles/meteor-collection-helpers
I'm very familiar with PWR, but collection-helpers is new to me. It looks like the two are complimentary.
PWR solves the somewhat complex problem of publishing documents to the client via a reactive join based on arbitrarily complex relationships. See this question for more details.
collection-helpers appears to be a set of convenience functions added to the client to be used when traversing collection relationships inside of a template (given that the required documents have already been published). For example, if you have books and authors in separate (but related) collections, you can immediately get myBook.author.fullName inside of a template without having to type out the extra find for the author.
currently the top popular solution in atmosphere seems to be publish-composite https://atmospherejs.com/reywood/publish-composite

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