DAO | An implementation of DAO pattern for CoreData and Realm | Database library

I created Dao Repository that uses jdbc for working with DB.

I autowired this repository in my Service class.

Then I try to autowire my service class in my test class.

I am making a decentralized exchange in which I am trying to implement a search functionality where users put either token address, name, or symbol. But the challenge I am facing is that when users search for tokens like BUSD the token present in the user wallet will come on top. for example:-

suppose I have these tokens in my wallet and I am getting this response from web3

Upgrading kotlin to 1.6.0 causes Room Dao suspend modifier to break build project with error: "Not sure how to handle query method's return type........".

Are there(here) any solutions other than a workaround for running Dao functions withContext(Disapatchers.IO) in repository?

I was using Android Room library in my project to manipulate data from my SQLite database and everything was working fine in previous Kotlin version (1.5.31). Here is a sample of my DAO:

I would like to have the preview of my HomeScreen composable function in my HomeScreenPrevieiw preview function. However this is not being possible to do because I am getting the following error:

I'm trying to follow this documentation here concerning how to unit test a PagingData stream on which you're applying transforms. The code I am using is similar:

I have a question regarding the @GeneratedValue annotation from Spring JPA.

This is my class:

As stated in official documentation, it's preferable to use the Multimap return type for the Android Room database.
With the next very simple example, it's not working correctly!

This question is somehow related to my last question, because it is the same project but now I am trying to go one more step forward.

So, in my previous question I only had one table; this time I have two tables: the new second table is supposed to contain related attributes for the rows of the first table, in a OneToMany relationship. So, I store a ForeignKey in the second table that would store the Row ID of the first table's related row (obviously).

The problem is this: the intention is creating both registers (parent and child) at the same time, using the same form, and ParentTable uses AUTO_INCREMENT for his PrimaryKey (AKA ID).

Due to how RoomDb works, I do the creation using a POJO: but after insertion, this POJO won't give me the auto-generated ID as far as I know... so, the only workaround I am able to imagine is, when submitting the form, first make the INSERT for the parent, then using one of the form's fields that created the parent to make some kind of "SELECT * FROM parent_table WHERE field1 LIKE :field1", retrieving the ID, and then use that ID to create the child table's POJO and perform the next INSERT operation. However I feel something's not right about this approach, the last time I implemented something similar this way I ended up with a lot of Custom Listeners and a callback hell (I still have nightmares about that).

About the Custom Listeners thing, it is the solution I ended up choosing for a different problem for a different project (more details about it in this old question). Taking a look to that old question might help adding some context about how misguided I am in MVVM's architecture. However, please notice the current question has nothing to do with WebServices, because the Database is purely local in the phone's app, no external sources.

However, I am wondering: isn't this overkill (I mean the INSERT parent -> SELECT parentID -> INSERT child thing)? Is it inevitable having to do it this way, or there is rather a more clean way to do so?

The "create method" in my Repository class looks like this: