Tutorial by Examples: en

Nested serializers by default don't support create and update. To support this without duplicating DRF create/update logic, it is important to remove the nested data from validated_data before delegating to super: # an ordinary serializer class UserProfileSerializer(serializers.ModelSerializer): ...

The only way if your components does not have a parent-child relationship (or are related but too further such as a grand grand grand son) is to have some kind of a signal that one component subscribes to, and the other writes into. Those are the 2 basic operations of any event system: subscribe/li...

This fetches the value of NOW() in local time, in India Standard Time, and then again in UTC. SELECT NOW(); SET time_zone='Asia/Kolkata'; SELECT NOW(); SET time_zone='UTC'; SELECT NOW();

SELECT NOW(3) does the trick.

Javascript timestamps are based on the venerable UNIX time_t data type, and show the number of milliseconds since 1970-01-01 00:00:00 UTC. This expression gets the current time as a Javascript timestamp integer. (It does so correctly regardless of the current time_zone setting.) ROUND(UNIX_TIMEST...

authenticate_with_http_token do |token, options| @user = User.find_by(auth_token: token) end You can test this endpoint with curl by making a request like curl -IH "Authorization: Token token=my-token" http://localhost:3000

Here's an example of a React component with a "managed" input field. Whenever the value of the input field changes, an event handler is called which updates the state of the component with the new value of the input field. The call to setState in the event handler will trigger a call to ...

For a non-main packages as well as main, instead of adding flags inside the code, write benchmarks in the test package , for example: func BenchmarkHello(b *testing.B) { for i := 0; i < b.N; i++ { fmt.Sprintf("hello") } } Then run the test with the profile flag ...

grant all privileges on schema_name.* to 'new_user_name'@'%' identified by 'newpassword'; Attention: This can be used to create new root user

rename user 'user'@'%' to 'new_name`@'%'; If you create a user by mistake, you can change his name

You might receive from your peer private key in PPK format, which seems it does not work in OpenSSH (command-line ssh). The client will be asking for the passphrase, because of OpenSSH bug. $ ssh -i mykey.ppk example.com Enter passphrase for mykey.ppk: You need to convert the key to OpenSSH for...

Visual Basic.NET, like most languages, permits recursion, a process by which a function calls itself under certain conditions. Here is a basic function in Visual Basic .NET to compute Fibonacci numbers. ''' <summary> ''' Gets the n'th Fibonacci number ''' </summary> ''' <param na...

variables this local arguments

This function shortens the text to a specified number of words and returns the shortened text. <?php echo wp_trim_words( get_the_content(), 40, '...' ); ?> In the above example we are passing the post content to the function. It will restrict the length of the content to 40 words and will ...

There are two kinds of persistent storage modes in Redis: AOF and RDB. To temporarily disable RDB execute the following commands on the Redis command line: config set save "" to temporarily disable AOF execute the following from the Redis command line: config set appendonly no The...

The following code will get the current configuration for the persistent storage state. These values can be modified dynamically, so they may differ from the configuration in redis.conf: # get config get appendonly config get save

To generate the coverage information the compiled program should be executed. When creating code coverage for a test suite this execution step will normally be performed by the test suite so that the coverage shows what parts of the program the tests executes and which they do not. $ a.out Execu...

You can use conditional operators in WordPress to enqueue scripts on specific pages of your Website. function load_script_for_single_post(){ if(is_single()){ wp_enqueue_script( 'some', get_template_directory_uri().'/js/some.js', array...

data table; set table; label variable1 = 'label1' variable2 = 'label2' variable3 = 'label3'; run;

In this example, we will launch a basic EC2 Instance with Amazon Linux in the quickest manner possible via the AWS Management Console. Amazon frequently improves the user experience of the AWM Management console, so you might experience some changes to the screens below. Important: launching an in...