Issue with relation when creating record - google-app-maker

Question

I have two tables that are related as follows:
PMLprojects ONE - MANY Inovice_stat
I have a script to create a record in the Invoice_stat table. It goes as follows:
var myProjectList = app.datasources.PMLprojects;
var myProjectListID = myProjectList.Id;
var myDatasource = app.datasources.Invoice_stat;
var myCreateDatasource = myDatasource.modes.create;
now = new Date();
var draft = myDatasource.modes.create.item;
draft.EmailStatus = "Yes";
draft.PaidStatus = "No";
draft.DateCreate = now;
myCreateDatasource.createItem(function(newRecord) {
var key = newRecord._key;
});
myDatasource.saveChanges();
All the fields are properly populates except the relation to PMLprojects. How can I related the record from Invoice_stat to PMLprojects? I'm getting the following message:
Error log :
com.google.apps.appmaker.client.datasource.AbstractModelDataSource
WARNING: Could not select element with key RecordKey{key=private$6,
model
key=1Y8Ijd68IZyWFllY3d_C9fhAOFtVgKCtH|Gu5LnmmFmZHfEbrL5Ug1fybNaVLSEPn6}.
No records bound.

Answer 1

Here is some proposed edited code for you to try. However, do remember that if your PMLprojects datasource is not loaded on the client, then this will still fail. I also highly recommend that you check out the official documentation here https://developers.google.com/appmaker/models/relations#modify_associations.
var myProjectList = app.datasources.PMLprojects.item; //change this line to point to an item in the datasource
//var myProjectListID = myProjectList.Id; This line is not necessary
var myDatasource = app.datasources.Invoice_stat;
var myCreateDatasource = myDatasource.modes.create;
now = new Date();
var draft = myCreateDatasource.item; //you already declared the create mode
draft.EmailStatus = "Yes";
draft.PaidStatus = "No";
draft.DateCreate = now;
draft.YourRelationToPMLprojects = myProjectList; //here is where you create your relation, replace YourRelationToPMLprojects with your actual relation name should show up in code autocomplete
myCreateDatasource.createItem(function(newRecord) {
var key = newRecord._key;
});
myDatasource.saveChanges();

Answer 2

Since you are probably using both tables with the Manual Save mode... then #MarkusMalessa's approach might return you an error. If that is so, you have to make sure that you create the relation after you create the item but before you save changes. For that, take into consideration the following example:
var project = app.datasources.PMLprojects.item; //project item
var ds = app.datasources.Invoice_stat;
var createDs = ds.modes.create;
var draft = createDs.item;
draft.EmailStatus = "Yes";
draft.PaidStatus = "No";
draft.DateCreate = new Date();
createDs.createItem(function(){
ds.item.PMLproject = project; //here is where you create your relation
ds.saveChanges();
});
Just remember, this will only work as long as the PMLprojects datasource has already been loaded, otherwise you will probably get an error.