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By utilizing the pre_save we can determine if a save action on our database was about updating an existing object or creating a new one. In order to achieve this you can check the state of the model object: @receiver(pre_save, sender=User) def pre_save_user(sender, instance, **kwargs): ...

An example of a constraint as expressed in the C standard is having two variables of the same name declared in a scope1), for example: void foo(int bar) { int var; double var; } This code breaches the constraint and must produce a diagnostic message at compile time. This is very usef...

The members of a union share the same space in memory. This means that writing to one member overwrites the data in all other members and that reading from one member results in the same data as reading from all other members. However, because union members can have differing types and sizes, the da...

Suppose, that we have three users : The Administrator of the database > admin The application with a full access for her data > read_write The read only access > read_only With below queries, you can set access privileges on objects created in the future in specified schema. ALTER ...

When calling driver.Navigate().GoToUrl(url);, the code execution stops until the page is fully loaded. This is sometimes unnecessary when you just want to extract data. Note: The code samples below could be considered hacks. There is no "official" way of doing this. Create a new thread...

XML <Animal> <legs>4</legs> <eyes>2</eyes> <horns>2</horns> <tail>1</tail> </Animal> XPATH boolean(/Animal/tusks) OUTPUT false

XPATH <Animal> <legs>4</legs> <eyes>2</eyes> <horns>2</horns> <tail>1</tail> </Animal> XPATH boolean(/Animal/horns) OUTPUT true

XML <House> <LivingRoom> <plant name="rose"/> </LivingRoom> <TerraceGarden> <plant name="passion fruit"/> <plant name="lily"/> <plant name="golden duranta"/> ...

select * from dict

The Lorenz model describes the dynamics of three state variables, X, Y and Z. The model equations are: The initial conditions are: and a, b and c are three parameters with library(deSolve) ## ----------------------------------------------------------------------------- ## Define...

Dim count As Integer = 0 Dim message As String If count = 0 Then message = "There are no items." ElseIf count = 1 Then message = "There is 1 item." Else message = "There are " & count & " items." End If

Getting You Browser Ready - Polyfill it Create a new landing page for our element, at index.html. Include polyfills for a custom element to work.Also import the custom element g-map, which we registered with Polymer. Note: Webcomponents, are the necessary polyfill for browser support. Polym...

<link rel=import href="../bower_components/google-map/google-map.html"> <link rel=import href="../bower_components/google-map/google-map-marker.html"> <link rel=import href="../bower_components/google-map/google-map-search.html"> <link rel=import...

Sample uses Install-Package Google.Apis.AnalyticsReporting.v4 Public Shared Function getServiceInitializer() As BaseClientService Dim serviceAccountCredentialFilePath = "Path to Json service account key file" REM from Google Developers console Dim myKeyEMail ...

There are two kinds of programs the kernel knows of. A binary program is identified by it's ELF (ExtenableLoadableFormat) header, which is usually produced by a compiler. The second one are scripts of any kind. If a file starts in the very first line with the sequence #! then the next string has to...

First Execute CREATE EXTENSION DBLINK; Then INSERT INTO <SCHEMA_NAME>.<TABLE_NAME_1> SELECT * FROM DBLINK( 'HOST=<IP-ADDRESS> USER=<USERNAME> PASSWORD=<PASSWORD> DBNAME=<DATABASE>', 'SELECT * FROM <SCHEMA_NAME>.<TABLE_NAME_2...

Android supports fingerprint api from Android 6.0 (Marshmallow) SDK 23 To use this feature in your app, first add the USE_FINGERPRINT permission in your manifest. <uses-permission android:name="android.permission.USE_FINGERPRINT" /> Here the procedure to follow ...

Snippet from MyExampleFile.xaml <TextBlock Foreground="{ThemeResource SystemControlBackgroundAccentBrush}" Text="This is a colored textbox that use the Accent color of your Windows 10"/> <TextBlock Foreground="{ThemeResource SystemControlBackgroundBa...

Snippet from MyExampleFile.xaml <TextBlock x:Name="MyTextBlock" Text="This is a TextBlock colored from the code behind"/> Snippet from MyExampleFile.xaml.cs // We use the application's Resource dictionary to get the current Accent of your Windows 10 ...

sample json to update { "student":{"name":"Rahul", "lastname":"sharma"}, "marks":{"maths":"88"} } To update the elements value in the json we need to assign the value and update. try { // Create a new in...