Overwriting records that match in Collection using LoadData

[mauritsbouman]

Hello Power Apps Community,

First of all, I am using this line of code to create a collection OnStart and fill it with my data:

ClearCollect(MeasurementLines; AddColumns('[dbo].[CRONUS Nederland BV$Measurement Lines]'; "showError"; false; "showWarning"; false; "userName"; ""; "DateTime"; ""; "OutgoingGoods"; "")

This collection is filtered on Line Type attribute and is then displayed in a Gallery with a text input.
OnChange of the Text Input will patch the selected item when entry is correct using this code:

Patch(MeasurementLines; ThisItem; {'Measured value': Value(MeasurementInput.Text)}; {showError: false}; {showWarning: false}; {userName: UserInformation.FullName}; {DateTime:Now()})

After the patch, in the same OnChange, I have put in this code:

SaveData(MeasurementLines; "SavedMeasurementLines")

When opening the application, I want to prioritize records from LoadData over collecting the items from the datasource. I want to end up with the records from LoadData (if not empty) and the rest of the records from the datasource, but all in the same collection called MeasurementLines.

Does anyone know how to implement this?