Tutorial by Examples: action

Using alarm, user can schedule SIGALARM signal to be raised after specified interval. In case user did not blocked, ignored or specified explicit signal handler for this signal, the default action for this signal will be performed on arrival. Per specification default action for SIGALARM is to termi...

Whenever you change data, in a Data Manipulation Language(DML) command, you can wrap your changes in a transaction. DML includes UPDATE, TRUNCATE, INSERT and DELETE. One of the ways that you can make sure that you're changing the right data would be to use a transaction. DML changes will take a loc...

In order for a program to react to a certain signal, other than using default action, custom signal handler can be installed using sigaction. sigaction receives three arguments - signal to act on, pointer to sigaction_t structure which, if not NULL, is describing new behaviour and pointer to sigacti...

Though the transaction class method is called on some ActiveRecord class, the objects within the transaction block need not all be instances of that class. This is because transactions are per-database connection, not per-model. In this example a balance record is transactionally saved even though ...

Both #save and #destroy come wrapped in a transaction that ensures that whatever you do in validations or callbacks will happen under its protected cover. So you can use validations to check for values that the transaction depends on or you can raise exceptions in the callbacks to rollback, includin...

ActiveRecord::Base.transaction uses the ActiveRecord::Rollback exception to distinguish a deliberate rollback from other exceptional situations. Normally, raising an exception will cause the .transaction method to rollback the database transaction and pass on the exception. But if you raise an Activ...

Another powerful & mature concurrency tool in Haskell is Software Transactional Memory, which allows for multiple threads to write to a single variable of type TVar a in an atomic manner. TVar a is the main type associated with the STM monad and stands for transactional variable. They're used m...

UISplitViewController must be the rootViewController of your application. AppDelegate.m - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch. self.window = [[UIWindow alloc] i...

Multiple operations can be executed against a single transaction so that changes can be rolled back if any of the operations fail. using (var context = new PlanetContext()) { using (var transaction = context.Database.BeginTransaction()) { try { //Lets assum...

ActionMailer supports three callbacks before_action after_action around_action Provide these in your Mailer class class UserMailer < ApplicationMailer after_action :set_delivery_options, :prevent_delivery_to_guests, :set_business_headers Then create these methods under the private ...

Alert controller has a property which is used to put emphases on an action added in the alert controller. This property can be used to highlight a particular action for user attention.For objective C; @property(nonatomic, strong) UIAlertAction *preferredAction An action which is already added in...

This will rollback both inserts due to an invalid datetime: BEGIN TRANSACTION BEGIN TRY INSERT INTO dbo.Sale(Price, SaleDate, Quantity) VALUES (5.2, GETDATE(), 1) INSERT INTO dbo.Sale(Price, SaleDate, Quantity) VALUES (5.2, 'not a date', 1) COMMIT TRANSACTION END TRY BEG...

#Persistent Menu, Tray, NoStandard ; remove default tray menu entries Menu, Tray, Add, MyDefaultAction, OnDefaultTrayAction ; add a new tray menu entry Menu, Tray, Add, Exit, Exit ; add another tray menu entry Menu, Tray, Default, MyDefaultAction ;When doubleclicking the tray icon, run the tra...

Starting with the Support Library version 22.2.1, it's possible to show and hide a FloatingActionButton from scrolling behavior using a FloatingActionButton.Behavior sublclass that takes advantage of the show() and hide() methods. Note that this only works with a CoordinatorLayout in conjunction wi...

Abstraction levels help determine when to split things up. Abstraction is achieved by implementing functionality with increasingly detailed code. The entry point of a macro should be a small procedure with a high abstraction level that makes it easy to grasp at a glance what's going on: Public Sub...

Spark uses lazy evaluation; that means it will not do any work, unless it really has to. That approach allows us to avoid unnecessary memory usage, thus making us able to work with big data. A transformation is lazy evaluated and the actual work happens, when an action occurs. Example: In [1]: li...

Problem By default, Django immediately commits changes to the database. When exceptions occur during a series of commits, this can leave your database in an unwanted state: def create_category(name, products): category = Category.objects.create(name=name) product_api.add_products_to_cate...

A transaction is a sequential group of SQL statements such as select,insert,update or delete, which is performed as one single work unit. In other words, a transaction will never be complete unless each individual operation within the group is successful. If any operation within the transaction fai...

with q command we could simplify a lot of tedious work in vim. example 1. generate array sequence (1 to 20). STEP 1. press i to enter insert mode, input 1 1 STEP 2. Record following action: "append the last number to the next line, and increment the number" type esc to exit input...

You can set the behavior of the FAB in XML. For example: <android.support.design.widget.FloatingActionButton app:layout_behavior=".MyBehavior" /> Or you can set programmatically using: CoordinatorLayout.LayoutParams p = (CoordinatorLayout.LayoutParams) fab.getLayoutPara...