electrician | Wires components into systems | User Interface library

I'm attempting to map to a lookup table that contains values for multiple tables. I cannot modify the database. The table has a one-to-many relationship with multiple tables, but no foreign key constraints. The lookup table has three columns code, category and description. A sample set of the data would look like this:

Lookup table:

I'm interested in joining the Activity table that looks like this (some columns omitted for clarity):

Activity table:

I want to join the Activity table to the Lookup table using EF Core. If I was writing a SQL statement I'd just have something like this:

I have data that has a row for each job change for an employee, is there a way to count the unique jobs changez a person has had like below without using sub queries?

I have a custom component class that displays a select list using React Native Picker in an app. This component is imported by one of the screens that I have created using createBottomTabNavigator() of react navigation.

The screen that uses this class has a form. The user fills the form and on submission the user is directed to another screen. What I am struggling at is that when the user returns to the same form screen instead of Picker list been resetted to its default value I am seeing the list with the previous selected value. How do I reset it when the form is submitted from the class

the Picker list component is as follows

I'm trying to create a grouped queryset in Django to first group by occupation and then aggregate sum of occupation by date_rented where date_rented is grouped by month.

I have been able to accomplish getting the desired results in python but it seems rather inefficient to me as it is necessary to do subqueries for each occupation to get the sum according to date_rented. Failing being able to use Django's built-in query API, I suppose I will have no choice but to use this solution, but if anyone can help me solve this using Django built in query API, I will be eternally grateful.

Model

this is the code I wrote, and I have been getting the error.

What I am trying to do is that Client have 2 child classes "CASUAL_JOB and CONTRACT_JOB" but these 2 classes have Client No (primary key of Client Table) under different Heading. So my target is to find total cost (info in Invoice Table) which is integrated with JobID (present in Invoice, Contract_Job, Contract_job Tables) and retrieve Client Info from Client Table

(+) is for left Outer Joint

I am sure this question has been asked in many forms before, but I am struggling to find something to clarify my understanding.

As far as I understand it, the concept of asynchronously running certain sections of code in .Net is based around sending work off into multiple threads so that it can run in parallel with other work. In some cases we need to wait for this work to be finished before we can get on with the next thing and in others we don't. I am mainly confused about how to handle these differences.

There are various analogies I can use, but let's look at a builder, or team of builders building a house. At various stages the team are working together on separate tasks, or together on one, here's a very simplified walk-through.

1. The first task is groundworks. There's nothing to go on, so everyone has to work on digging footings.
2. We need groundworks to complete before we can do anything else.
3. Once groundworks are completed We start blockwork and put the walls up.
4. Now we have walls the electricians and plumbers come in
5. Their respective tasks are sent off to each trades team and run in parallel to install first-fix wiring and pipe work.
6. In the meantime, someone has contacted Royal Mail to get this new address added to their postcode/address database.
7. Plumbers and electricians are done so we can start plasterboarding. ..... etc

In this analogy, we have three types of Task;

• The first two jobs (groundworks and blockwork) have to be completed before anything else can be done, so we are running them in series in a main work thread.
• The electricians and plumbers are two separate threads running together, they don't need to wait for each other to finished, but we will likely need to know whether either or both have finished.
• The postcode database has no impact on the building of our new house, so as a builder we have no interest in that, we just send it off to a different team (Royal Mail) and they do their thing and we have no real need to know when it is done so it's a send and forget task.

I found this question on SO:

How to put this function inside a separate thread

It is quite helpful, mainly the response from "igrimpe", I will copy his code:

Suppose I have a class as follows.

Is there a way to implement this: I have got a datatable displayed and I would like to toggle a particular row if a row index is selected and a toggle button is clicked. I just want to hide the row, not deleting from the datatable completely. I have got the ui as following. How to implement the server side?