I have a database where I store player names that belong to people who have certain items.
The items have and IDs, and subIDs.
The way I am currently storing everything is:
Each ID has its own collection
Within the collection there is a document for each subID.
The document for each subID is layed out like so:
{
"itemID":itemID,
"playerNames":[playerName1, playerName2, playerName3]
}
I need to be able to add to the list of playerNames quickly and efficiently.
Thank you!
If I understood your question correctly, you need to add items to the "playerNames" array. You can use one of the following operators:
If the player names array will have unique elements in it, use $addToSet
Otherwise, use $push
Related
I have a list of constructed objects called RecentCard which is basically an object with user id, pic, and name. I have created a list arranged in order of most recent interaction based on timestamp. However i need to get rid of the second occurence and onwards of any duplicated object. I am comparing just the ids since users may have the same name or photo, and i cannot remove duplicates from a simple list of uids because then i could lose the order of corresponding photos and names.
For example the list would look something like this :
List<RecentCard> recentCards= [RecentCard(uid:as721dn18j2,name:mike,photourl:https://sadadasd1d1),RecentCard(.....]
I have searched for solutions but all of them are dealing with like primitive types like simple lists of strings and the solutions didn't work for me. For example this post: How to delete duplicates in a dart List? list.distinct()? Read below
The first answer's link is no longer available, the next answer with sets is something i tried but it simply doesnt work i have no idea why maybe because its not a primitive type. The next answer with the queries package didn't work because i was using the list to build a listview.builder and so when i called list.length it said i couldnt call that on an iterable or something. The final solution wouldn't work because it said String is not a subtype of RecentCard.
I tried using two forloops with the second just comparing first value to the next couple but that doesnt work because if a duplicate is found, the object is removed and the length is messed up so some elements get skipped.
Any ideas? I feel like its very simple but im not sure how to do it.
You have to use Set to store seen cards and then filter away those ones that are already in the set.
final seenCards = Set<String>();
final uniqueCards = recentCards.where((card) => seenCards.add(card.uid)).toList();
basically my whole career is based on reading question here but now I'm stuck since I even do not know how to ask this correctly.
I'm designing a SQLITE database which is meant for the construction of data sheets out of existing data sheets. People like reusing stuff and I want to manage this with a DB and an interface. A data sheet has reusable elements like pictures, text, formulas, sections, lists, frontpages and variables. Sections can contain elements -> This can be coped with recursive CTEs - thanks "mu is too short" for that hint. Texts, Formulas, lists etc. can contain variables. At the end I want to be able to manage variables which must be unique per data sheet, manage elements which are an ordered list making up the data sheet. So selecting a data sheet I must know which elements are contained and what variables within the elements are used. I must be able to create a new data sheet by re-using elements and/or creating new ones if desired.
I came so far to have (see also link to screen shot at the bottom)
a list of variables
which (several of them) can be contained in elements
a list of elements
elements make up the
a list of data sheets
Reading examples like
Store array in SQLite that is referenced in another table
How to store a list in a column of a database table
give me already helpful hints like that I need to create for each data sheet a new atomic list containing the elements and the position of them. Same for the variables which are referenced by each element. But the troubles start when I want to have it consistent and actually how to query it.
How do I connect the the variables which are contained within elements and the elements that are contained within the data sheets. How do I check when one element or variable is being modified, which data sheets need to be recompiled since they are using the same variables and/or elements?
The more I think about this, the more it sounds like I need to write my own search tree based on an object oriented inheritance class structure and must not use data bases. Can somebody convince me that a data base is the right tool for my issue?
I learned data bases once but this is quite some time ago and to be honest the university was not giving good lectures since we never created a database by our own but only worked on existing ones.
To be more specific, my knowledge leads to this solution so far without knowing how to correctly query for a list of data sheets when changing the content of one value since the reference is a text containing the name of a table:
screen shot since I'm a greenhorn
Update:
I think I have to search for unique connections, so it would end up in many-to-many tables. Not perfectly happy with it but I think I can go on with it.
still a green horn, how are you guys using correct high lightning for sql?
I've been racking my brain over the past several days trying to find a solution to a storage/access problem.
I currently have 300 unique items with 10 attributes each (all attributes are currently set as strings but some of the attributes are numerical). I am trying to programmatically store and be able to efficiently access attributes based on item ID. I have attempted storing them in string arrays, vectors, maps, and multimaps with no success.
Goal: to be able to quickly access an item and one of its attributes quickly and efficiently by unique identifier.
The closest I have been able to get to being successful is:
string item1[] = {"attrib1","attrib2","attrib3","attrib4","attrib5","attrib6","attrib7","attrib8","attrib9","attrib10"};
I was then able to access an element on-demand by callingitem1[0]; but this is VERY inefficient (particularly when trying to loop through 300 items) and was very hard to work with.
Is there a better way to approach this?
If I understand your question correctly it sounds like you should have some sort of class to hold the attributes, which you would put into a map that has the item ID as the key.
Ok, I have to use Flex 3 because I am using this in an Adobe Connect pod. I have a List component, which is capable of being reordered through drag and drop. If someone leaves the browser and comes back into the meeting room, I am trying to redisplay how they had items ordered from their drag and drop. So I need a way to reorder the list. I was looking into sort for Arrays on the dataProvider. But I have not been able to figure out the proper event to sort the list once, all of the items have the appropriate data in.
In any case, does anyone know how to tell the data of an itemRenderer to have ordered values, and then tell the list to reorder the items in the list according to the new values?
One of the possible ways I used:
Keep your data in Object(map) with key:value, Object{rowIndex:rowData}
e.g. {1 : row1Data,
2 : row2Data, ... }
Prepare the list values based on the keys and then assign it to the grid. This way, Itemrenderer will no longer need to know the "order" of the data. Their task is just to display the data.
Once user is done with drag-drop - update the map, persist it.
Hope this helps.
If you use an ArrayCollection, you can apply a sort, and then call arrayCollection.refersh() to refresh the collections with the sort, which will then update the list display
I've got a spark list that gets dynamically filled.
So far the new items appear at the bottom of the list. What I'd like to do is to add them at the top.
The items in the list have a unique ID so some kind of sorting mechanism would probably do the trick as the new items have a greater ID than the old ones.
What I'd like to avoid is some complex method behind this as I'm working on a mobile platform and the list can get quite big so I need this to be as efficient as possible.
The list's data provider is an ArrayList that gets updated using binding.
How can that be done?
Thanks in advance!
u can Add the items at the starting index of the datagrid. Flex datagrid automatically renew all the indexes and add 1 to all existing element indexes. So
YourDataGridId.dataprovider.addItemAt(item,0) will do.