I've a simple chat in swift and I retrieve 10 elements with queryLimitedToLast.
I want retrieve more element with a refresh function. How can increase the number of elements?
I've try to set the value in queryLimitedToLast with a variable but don't works.
Thanks!
Firebase Queries are immutable; once you've created them, you cannot modify them.
So you'll have to create a new query, which starts at the end of the previous query.
Related
I have an array of UIDs (String) and I want to perform a query using Firestore where I get all the documents in which the field "uid" is equal to any of the ones in the array provided.
Till now I tried doing:
ref.whereField("uid", in: uidArray)
But this doesn't work and gives me an error because the maximum number of elements in the array must be 10 and it surely surpasses that limit.
My question is: how can I achieve the same result with a workaround using Firestore?
Whenever I try to implement a query using this DB it seems it's built for making developers' lives harder.
Yes, according to the docs, the maximum number of elements in the array is 10. To be able to get over this limitation, you should perform successive calls. For example, if you need to check a field against 35 values, then you should perform 4 queries. Three queries with the 10 elements and the fourth with 5 elements. Lastly, you should combine the result on the client.
I am reading from a google sheet of 100,000+ records but I want to load only the records after a certain date. ( so applying filter ) . But I haven't been able to accomplish that as I do not know how to access the column name without using foreach.
Here is what the data looks like from the googlesheet
So basically, I would like to filter the records something like this.
Timestamp ge '10/13/2021' so it will only return records for 10/13/2021 and 10/14/2021... etc.
Is this possible to do that? If not, what is the best recommended way to approach this issue as i just wanted to load daily records to sql db in the next step.
The Get rows action of the Google Sheets connector doesn't support filtering. You can only specify how many rows you want returned, and how many rows you want to skip. E.g. if you have 100,000 rows in your sheet, you can easily get the rows between 90,001 and 90,200, should you wish to do so.
While you can't use this connector to retrieve filtered data from Google Sheets, you can use the Filter array action to filter the retrieved data as you wish.
You might still need to use the For each loop to retrieve and filter data in chunks.
Here i'm using firestore query to update, insert data. How to upadate dictionary of array value to firebase database.
here is my firestore data structure:
Right now able to get data of slot1 -> 0th position value in a model class.
how can i update value of slot1 0th position of isbooked boolean value alone, without affecting remaining values and other slot.
You can't without reading the entire document, modifying the array data in memory, then updating the entire array field back out do the document. The smallest unit of change in a Firestore array field is an entire field. You can't make smaller changes to individual elements of a field, except those defined by arrayUnion and arrayRemove (which are not compatible with what you're trying to do here).
You can do that by getting the exact id of your structure ..
Database.database().reference().child("SlotName").child(yourAry.key).child(yourAry.key).child("isbooked").setValue(true/false)
Manage your database structure accordingly, its just an example and as user Doug suggested have a look on docs too ..
I am working on an application that retrieves the posts from firebase. The problem is I want to retrieve the first 20 posts and show in a table. When a user clicks the next button, it will retrieve the next 20 posts and show and so on.
I know firebase provides the following methods
queryLimitedToFirst
queryLimitedToLast
queryStartingAtValue
queryEndingAtValue
queryEqualToValue
But how do I use them in conjunction to retrieve the desired results like I want?
Here is the structure of the data I have:
You should order query by some property (I usually use timestamp). This organises your orders from latest to oldest. When you have them ordered you should limit them:
queryOrdered(byChild: "timestamp").queryLimited(toLast: UInt(limit))
As you can see we can limit results to whatever number we like. You can use this to read your posts each time for 20 results more.
So the first time you call it with a limit of 20, next time with a limit of 40, etc. Keep in mind that this will return posts that were already returned in the previous call.
Instead you could combine it with queryStartingAtValue and use your last post tiemstamp - this will "skip" your previous results and return only 20 posts you need.
This is just an idea but I think it should work like expected.
I'm using Firebase for my iOS application and I'm having trouble implement infinite scroll and filtering data together.
What I need to do is:
Display items with order/filter on multiple property (location, category, status . . .)
Implement infinite scroll when the user scrolled to bottom of the screen.
I tried to think about some solutions:
The first, I think that I'll query the data with the necessary conditions then limit the number of records by use queryLimitedToFirst(N), and increase N when need to load the next items. But because Firebase can only filter on one property at a time and it's also a waste to reload data. So, I was thinking about the second solution.
As approaches are suggested from Frank van Puffelen (Query based on multiple where clauses in firebase):
filter most on the server, do the rest on the client
Yes, exactly like that. I'll execute queryOrderedByKey, queryStartingAtValue, queryEndingAtValue to implement infinite scroll, pull down the remaining data and filter that on client. But there is one problem that is I would not have enough items to display for the user if execute filter on the client.
For example: each time run the query, I receive 10 items. After data filtering process on the client, I just left 5 (can be 0) items meet the conditions to display to the user.
I don't want this because user may think there is a problem
Can I please get some pointers on this? If I didn't structured the data properly, can I also get some tips there?