Creating a Unique ID in a Collection

[jogar10]

Hello,

So I am currently building an app that has both online and offline capabilities. With the online functionality, I have a form connected to a SharePoint list which is technically my master list for all the raw data I am trying to collect through the app. With the form, I am essentially trying to track the start and finish of what I call an operation (a task of a specific process). For the OnSelect of the start and stop buttons, I set a variable to patch into my SharePoint list and I basically input the data I wanted into the respective fields as well as the exact time I hit the start button. Now when I hit the finish button I set that same variable to patch into my SharePoint list and then use the LookUp function to find the same ID I set it at that way it can update the stop time for that same row of data in my sharepoint list. Now with offline functionality, I already have it to where it can insert data into a collection, but is there a way to where when I hit the stop button, it also goes to find that row in the collection and insert the stop time? Any help and insight would be greatly appreciated. Thanks!

[RandyHayes]

@jogar10 

Since you are offline with the internal records, you will not have a primary key (the ID in this case) to reference.  AND, you will want to make sure you leave the ID blank so that when you are online, the Patch function knows to create a record and not to update one.

What I do often for this capability is to simply establish another column in the collection and when the row is created in the collection, assign a GUID to that column.

Then, your LookUp to that collection would be based on the GUID and not the ID.

In other words, you are creating a separate primary key for your collection while still maintaining the actual primary key.

You can base your formulas on a Coalesce of the GUID key and the ID key in order to lookup and update.

I hope this is helpful for you.

[jogar10]

What you said makes sense. However, I am having trouble trying to implement it into my code. Could you possibly show an example of how to do that? 

[RandyHayes]

@jogar10 

Which part of the process do you have question on?  The Formulas you have should center around the new ID and any writebacks should be based on the real ID column.

I am not familiar with your complete app design, so I am not sure where you are struggling.

[jogar10]

For the start button I have more fields than what are shown but this is the basic format of what I have:

If(Connection.Connected,Set(varnewItem,Patch('Sharepoint List',Defaults('Sharepoint List'),{Start Time: Now()})), Collect(colOfflineList,{Start_Time: Now()}));

For the end button, I have:

If(Connection.Connected,Set(varnewItem,Patch('Sharepoint List',Lookup('Sharepoint List',varnewItem.ID=ID),{Stop Time: Now()})),Collect(colOfflineList,{Stop_Time: Now()}));

Basically for both buttons I have it check if the app is connected to the internet. If the app is connected to the internet, it will upload the data directly to my sharepoint list by using the "Set" function to create a new variable to "Patch" into my list. I did add an ID column through the sharepoint list itself. If the app isn't connected to the internet then it will go to store it in a collection. Same thing for when I hit the stop button, it checks if there is internet, if so then it will upload the data directly to my sharepoint list and "Lookup" the variable that is set to the ID in sharepoint. If not, it will send the data to the collection. My main issue is that there is multiple things happening in the collection that when I hit stop, I don't want it to create a new row just for the stop time in my collection. If it could go back and find the original row tied to when it was started and input the stop data there, then that would be ideal. I just don't know how to fully work around that with a collection. Again, thank you for your time.

[RandyHayes]

@jogar10 

No problem.  

So- you are ONLY working with one record in your app??  I had assumed you had a table of records to work with.

Is that the case?

[jogar10]

If by records you mean multiple columns in the Sharepoint list/ collection, then I do. I just put the main column I would need to put information into when the stop button is pressed. I would like to find a way to look up for the specific ID in the collection but I don't know how to do that. If you meant by multiple collections/Sharepoint Lists, I have multiple of those as well. I just typed it in the way I did to simplify it. 

[RandyHayes]

@jogar10 

Well it was that you showed a collection that would end up with one record in it with one column at start and an added column at end.

Not understanding the role on that.  How does that then go to your datasource?  That would be more relevant to the example you provided...how are you getting the data initially from the datasource and how are you writing it back?

[jogar10]

I didn't show all the columns because the primary focus is the one with the start and stop time. Yes, there is other information that is pulled into it too. I have multiple different screens in the app that can pull different data that would be needed. For the app as a whole, with the OnStart, I have it set to where it will patch my collection into my Sharepoint List if it detects that it is online.  Lets say I have a customer order that I need to fill out. I have it to where it already populates that info to the worker using the app. The worker essentially needs to log their time for how long it takes them to complete that customer order. So, when they get that new customer order, they will fill a couple things and hit the start. Usually when they are online, they might run into other issues and will need to notify a supervisor pertaining to what it is. If that's the case I also have that to where it uploads onto my Sharepoint List, which is essentially the master list for all the data coming from the app. So if they start the customer order, then later decide they have an issue with it, it gets resolved, then they go to finish that customer order by hitting the stop button, then that is when the functionality of the buttons I showed earlier would be used to find the unique ID in the sharepoint list and log the finished time for that order. If they're offline, I need the stop time to go back for that same reason to keep the data consistent in one row and update to its respective column. I could just have it to where when I start the customer order, it will populate the columns in my collection and the start time. Then when I stop the customer order, it would create another row in the collection populating the same info but including the stop time instead of the start time. This isn't ideal because to my understanding, PowerApps has a limit to how much data you can store in a collection, and being able to put the finish time in the same row of the customer order would be more efficient.

[RandyHayes]

@jogar10 

Yes, so the thing with a Collection is that it has no primary key to it.  Usually, if you pull in a datasource set of records, it will "kind of" have that as a key (it's at least something you can reference as unique).  However, in your case, you do not have the luxury of always having the actual unique primary key in your collection...so you need to augment it. 

As mentioned, the way to do that is to assign your own unique ID for the purpose of the App only.  It is not meant to ever go to the datasource.  When you load your collection with records, add a column that will have a GUID in it.

When you create any new record, add the GUID too.

When you work with the records in your collection, always reference/identify by the GUID.

When you go to write your data back, THEN work from the primary key (ID) and discard the GUID to write back.  

Hopefully that makes sense.