Sturggling with Joins / PowerApp Design

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Posted on by ShowMeTheAnswer

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I saw this post but it seems to only partially answer the question.

https://powerusers.microsoft.com/t5/General-Discussion/Syntax-for-joining-tables/m-p/61425#M25380

I have several tables I designed, all linking to a "Main" table.

I also (in an attempt to solve the issue) created a "View" of what I'd like to see in PowerApps.

Also just to say I'm sorry if this is similar to my other post; it is; but I can't seem to make that logic work in this case.

I've made too attempts at creating PowerApps based on my data, as below:

1) Using "Gallery" - "SQL Datasource" - Select the relevant database, and later where relevant columns.

As an example, I selected the "MAIN" table. The Main table has a column (now called) "APPLICATION_ID".
The idea is, to pick from a List of Values, the list being the "Applications" in the Applications Table:

APP_ID APPLICATION PROCESSSTEP

1 Body Shop BIW Swindon Pressings

2 Paint Shop E-Coat Sand

3 E-Coat Repair Abrasive Discs 125mm

4 Masking Contrast Roof Abralon Sheets
So I can (sometimes) get the list of applications to appear (eventually I deleted everything and re-added my own "DataCard" and "DropDown control".
Then, everything goes screwy in one or more of the following ways:
- The data cannot be saved (at all) - e.g. new records can't be created; and existing records cannot be changed.
- The data is saved, but the MAIN_ID gets stored instead of the APP_ID

- Wierd Effects; possibly related to the above - as an example, the "Browse" screen shows one value (mostly it appears to the the MAIN_ID), and the "View" screen shows a different ID; and/or they change when the record loads/is selected.
Having spent several hours fiddling around with that and getting no luck or even consistent returns.

I tried:
2) Creating a "VIEW" in SQL, and linking all the ID's together correctly, so that it returns already the correct data.
The view seemed to work; but when you feed that as a data source to the new gallery app; everything is read only. In fact it doesn't even give you either a plus button for new records, nor an edit screen.

Any ideas? It seems to be almost unbeliable hard to do so something so simple; I'd have thought it would just handle all this rubbish for you instead of making it so hard. Especially after building a nice view defining the relationships between the data.

Like the poster in my link, I'm now thinking to just put every field onto one massive table; but that doesn't really work as a design and would result in many NULL columns.

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Building Power Apps

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ShowMeTheAnswer 109 on at

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Still struggling with this if anyone can help.
I hit on a new idea; of using a "VIEW" for the BrowseGallery & "Detail", and then switching to DBO.MAIN Table for the Edit.
It is apparently possible:
https://powerapps.microsoft.com/en-us/blog/decouplingbrowsegalleryfromforms/

But unfortunately doesn't work.
The edit screen is the issue, specifically the Items property.
I tried this:
EditForm (as suggested in the post): result underlined in Red as an error.
Then I thought you could look it up:
If(Text(editItem.MAIN_ID)<>"",LookUp('[dbo].[MAIN]',MAIN_ID=editItem.MAIN_ID),BrowseGallery1.Selected)
e.g. if the "editItem.MAIN_ID" is not null, then lookup the relevant record in DBO MAIN; otherwise use BrowseGallery1.Selected.
(It should cover "New" items as well as "editing existing items").
I can press the edit but it doesn't correctly edit the existing item.
I can try a new record but get a data error.
Any ideas?
Meneghino 6,949 on at

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Don't use forms in PowerApps but create your own. You will be able to use views but patch changes to the base table.
See here: https://baizini-it.com/blog/index.php/2017/09/28/powerapps-101-create-your-own-forms/
ShowMeTheAnswer 109 on at

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Thank you for the reply.
I'll try that if I run out of ideas completely.
Most of what I need is already in my app so I don't want to rebuild it all.
I'd be surprised if you (that way) can edit records in a SQL View so I thought those are read only by their nature..
Meneghino 6,949 on at

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You are correct. To clarify what I meant is that you can display the views and in the patch statement use the base table(s) as the first argument.
ShowMeTheAnswer 109 on at

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Whats the "Patch statement"? Do you have an example?
Meneghino 6,949 on at

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Step 21 of the blog I sent you the link to.
ShowMeTheAnswer 109 on at

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Started the tutorial, not going well:
Set Gallery1’s OnSelect property to
Set(SelectedId, ThisItem.ID)
This gives Red line and:
Incomptaible Type, We can't evaluate your formula because the context variable types are incompatiable with the types of values in other places in my app.

Next step, another Red Line straightaway:
Also set Gallery1’s TemplateFill property to
If(ThisItem.ID = SelectedId , LightBlue, RGBA(0, 0, 0, 0))
If(ThisItem.ID = SelectedId , LightBlue, RGBA(0, 0, 0, 0))
or for me:
If(ThisItem.MAIN_ID = SelectedId , LightBlue, RGBA(0, 0, 0, 0))
Either way the "=" is underlined with "invalid argument type"

I'll keep trying but it wasn't a great start.
I honestly do appreciate your help though because, I am really struggling with this problem (something that MS seems to have made needlessly complex).
Drrickryp Super User 2024 Season 1 on at

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Hi @ShowMeTheAnswer,
While I entirely agree with @Meneghino about the advantages of creating your own forms, If you want to fix the one you have, the problem is that your Item property for the form is unnecessarily complicated. The Item property of an Edit form is automatically ignored when the Form Mode is New so the If statement is redundant. The datasource for the Form must be a real datasource, not a collection and the Item property must reduce to match the datasource. The items property of the gallery can be a collection or a reshaped table from a datasource but the primary key must be exposed to be referenced from the Form's Item property. The only time you can use a simple BrowseGallery1.Selected in the Item property of the form is when the Items property for the Gallery is Identical to the datasource of the form.
LookUp('[dbo].[MAIN]',MAIN_ID=BrowseGallery1.Selected.MAIN_ID
Should be sufficient.
ShowMeTheAnswer 109 on at

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Thanks - I tried it, it doesn't error out.
But whatever I do, it doesn't let me "edit the current record".
I'll try and add some attachments to demonstrate.
There is 3 screens; browse, "view" and "edit".
Browse screen is connected to a MS SQL "View", so I can display data.
So is the "View" screen. It's the "Edit"/"New" screen where there is problems.
Formula currently used on "Edit" button:
EditForm(EditForm1);Navigate(EditScreen1, ScreenTransition.Cover,{editItem:LookUp('[dbo].[MAIN]',MAIN_ID=displayItem.MAIN_ID)})
Then some details from the edit screen/form:
"Edit Form 1":
Datasource: '[dbo].[MAIN]'
Default Mode: FormMode.Edit
"Items" property: LookUp('[dbo].[MAIN]',MAIN_ID=BrowseGallery1.Selected.MAIN_ID)

Results: Pressing edit takes you to the edit screen which just has one field in. You can set it, and save it, but it doesn't affect the record you were on, which remains with the same value. E.g. it's not saved anywhere.

I'm also in the middle of re-building it per the other poster.
ShowMeTheAnswer 109 on at

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This line:
If(NewRecord, "(new)", SelectedId in Gallery1.AllItems.ID, SelectedId, "(none)")
From step 16:
Set Label_ID’s Text property to
"ID: "&If(NewRecord, "(new)", SelectedId in Gallery1.AllItems.ID, SelectedId, "(none)")
Gives Red squiggle and
"This rule creates a circular reference between properties, which is not allowed".