QtCreator is, at the moment, the best tool to create a Qt application. In this example, we will see how to create a simple Qt application which manage a button and write text.
To create a new application click on File->New File or Project:
Then choose the Projects->Application->Qt Widge...
Commands:
expdp <bkpadmin>/<bkp123> parfile=<exp.par>
*Please replace the data in <> with appropriate values as per your environment. You can add/modify parameters as per your requirements. In the above example all the remaining parameters are added in parameter files as...
Prerequisite:
Prior to user import it is a good practice to drop the schema or table imported.
Commands:
impdp <bkpadmin>/<bkp123> parfile=<imp.par>
*Please replace the data in <> with appropriate values as per your environment. You can add/modify parameters as per...
Go will throw an error when there is a variable that is unused, in order to encourage you to write better code. However, there are some situations when you really don't need to use a value stored in a variable. In those cases, you use a "blank identifier" _ to assign and discard the assign...
/* these IN and OUT filerefs can point to anything */
filename in "anyfilehere.xlsx";
filename out "anyfilehere.xlsx";
/* copy the file byte-for-byte */
data _null_;
length filein 8 fileid 8;
filein = fopen('in','I',1,'B');
fileid = fopen('out','O',1,'B');
...
Take note of the email type: Type = 'text/html';
Filename myEmail EMAIL
Subject = "My Email Subject"
From = "[email protected]"
To = '[email protected]'
CC = '[email protected]'
Type = 'text/html';
Data _null_; File my...
For example, imagine a screen with 3 sections, laid out like this:
The blue box might be given a margin of 4,4,0,0. The green box might be given a margin of 4,4,4,0. The purple box margin would be 4,4,4,4. Here's the XAML: (I'm using a grid to achieve the layout; but this design principle applies...
Sometimes Android's logcat is running infinitely with errors coming from some process not own by you, draining battery or just making it hard to debug your code.
A convenient way to fix the problem without restarting the device is to locate and kill the process causing the problem.
From Logcat
03...
Mailbox processors can be used to manage mutable state in a transparent and thread-safe way. Let's build a simple counter.
// Increment or decrement by one.
type CounterMessage =
| Increment
| Decrement
let createProcessor initialState =
MailboxProcessor<CounterMessage>.Sta...
Starting from a sequence of static images (for example called frame01.jpg, frame02.jpg and so on) an animated gif can be created using the following command:
magick -delay 10 -loop 0 frame*.jpg animation.gif
-delay 10 sets the interval between the frames to 0.1 seconds
-loop 0 creates a...
"""
CannyTrackbar function allows for a better understanding of
the mechanisms behind Canny Edge detection algorithm and rapid
prototyping. The example includes basic use case.
2 of the trackbars allow for tuning of the Canny function and
the other 2 help with understanding h...
So let's say you have two different entities, something like this:
public class Person
{
public int PersonId { get; set; }
public string Name { get; set; }
}
public class Car
{
public int CarId { get; set; }
public string LicensePlate { get; set; }
}
public class MyDemoCon...
In the last example, you can see that EF figures out which column is the foreign key and where should it point to. How? By using conventions. Having a property of type Person that is named Person with a PersonId property leads EF to conclude that PersonId is a foreign key, and it points to the prima...
In the previous examples a car cannot exist without a person. What if you wanted the person to be optional from the car side? Well, it's kind of easy, knowing how to do one-to-many. Just change the PersonId in Car to be nullable:
public class Car
{
public int CarId { get; set; }
public s...
Let's move on to the other scenario, where every person can have multiple cars and every car can have multiple owners (but again, the relationship is bidirectional). This is a many-to-many relationship. The easiest way is to let EF do it's magic using conventions.
Just change the model like this:
...
You might want to rename the fields in the join table to be a little more friendly. You can do this by using the usual configuration methods (again, it doesn't matter which side you do the configuration from):
public class CarEntityTypeConfiguration : EntityTypeConfiguration<Car>
{
publi...
I have to admit, I'm not really a fan of letting EF infer the join table wihtout a join entity. You cannot track extra information to a person-car association (let's say the date from which it is valid), because you can't modify the table.
Also, the CarId in the join table is part of the primary ke...
