Tutorial by Examples: b

Preallocation. Mongo sets aside disk-space in empty containers, so when the time comes to write something to disk, it doesn't have to shuffle bits out of the way first. It does so by a doubling algorithm, always doubling the amount of disk space preallocated until it reaches 2GB; and then each preal...

Gotta rotate those log files, or they'll eventually eat up all of your disk space. Start with some research... mongodb-log-file-growth rotate-log-files Log files can be viewed with the following command... ls /var/log/mongodb/ But to set up log-file rotation, you'll need to do the following.....

db.posts.find().forEach(function(doc){ if(doc.commenters){ var firstCommenter = db.users.findOne({'_id': doc.commenters[0]._id }); db.clients.update({_id: doc._id}, {$set:{'firstPost': firstCommenter }}, false, true); var firstCommenter = db.users.findOne({'_id': do...

db.posts.find().forEach(function(doc){ if(doc.commentsBlobId){ var commentsBlob = db.comments.findOne({'_id': commentsBlobId }); db.posts.update({_id: doc._id}, {$set:{'comments': commentsBlob }}, false, true); } });

db.posts.find().forEach(function(doc){ db.accounts.update({_id: doc._id}, {$set: {'_id': doc._id.str }}, false, true); });

var newvalue = ""; db.posts.find().forEach(function(doc){ if(doc.foo){ newvalue = '"' + doc.foo + '"'; db.accounts.update({_id: doc._id}, {$set: {'doc.foo': newvalue}}); } });

var newvalue = null; db.posts.find().forEach(function(doc){ if(doc.foo){ newvalue = '"' + doc.foo + '"'; db.accounts.update({_id: doc._id}, {$set: {'doc.foo': newvalue}}); } });

db.posts.find().forEach(function(doc){ if(doc._id){ db.posts.update({_id: doc._id}, {$set:{ timestamp: new Date(parseInt(doc._id.str.slice(0,8), 16) *1000) }}, false, true); } });

var timestamp = Math.floor(new Date(1974, 6, 25).getTime() / 1000); var hex = ('00000000' + timestamp.toString(16)).substr(-8); // zero padding var objectId = new ObjectId(hex + new ObjectId().str.substring(8));

This project is a self-contained example done completely in the Interface Builder. You should be able to work through it in 10 minutes or less. Then you can apply the concepts you learned to your own project. Here I just use UIViews but they can represent whatever view you like (ie, button, label...

These functions are used to check Mouse Button Clicks. Input.GetMouseButton(int button); Input.GetMouseButtonDown(int button); Input.GetMouseButtonUp(int button); They all take the-same parameter. 0 = Left Mouse Click. 1 = Right Mouse Click. 2 = Middle Mouse Click. GetMouseButton i...

Backbone.js is made up of four separate components: Collections, Models, Routers, and Views. Each of these serve different purposes: Model - represents a single data object, but adds additional functionalities not provided by native JavaScript objects, such as an event system and a more conveni...

Use $state.transitionTo to go form one state to another. This is a low level method to transition and $state.go is the recommended way for most common use cases as it uses this method internally. $state.transitionTo(toState [, toParams] [, options]) toState - the state to transition to toPara...

Webhook Overview A WebHook is an HTTP callback: an HTTP POST that occurs when something happens; a simple event-notification via HTTP POST. A web application implementing WebHooks will POST a message to a URL when certain things happen. PubNub Presence Pubnub presence all about the user prese...

AndroidManifest.xml: <activity android:name="com.example.MainActivity" > <intent-filter> <action android:name="android.intent.action.VIEW" /> <category android:name="android.intent.category.DEFAULT" /> <categ...

Feature detection of classes can partly be done with the property_exists and method_exists functions. class MyClass { public $public_field; protected $protected_field; private $private_field; static $static_field; const CONSTANT = 0; public function public_function() {...

Here is a basic setting of the Header to change to a new page when a button is clicked. if(isset($_REQUEST['action'])) { switch($_REQUEST['action']) { //Setting the Header based on which button is clicked case 'getState': header("Location: http://NewPageForSta...

Unlike other programming languages, in a batch file a variable is substituted by its actual value before the batch script is run. In other words, the substitution is made when the script is read into memory by the command processor, not when the script is later run. This enables the use of variable...

Create a new project It can be just a Single View Application. Add the code Create a new Cocoa Touch Class file (File > New > File... > iOS > Cocoa Touch Class). Name it MyCollectionViewCell. This class will hold the outlets for the views that you add to your cell in the storyboard. ...

The following might have undefined behavior due to incorrect pointer alignment: char *memory_block = calloc(sizeof(uint32_t) + 1, 1); uint32_t *intptr = (uint32_t*)(memory_block + 1); /* possible undefined behavior */ uint32_t mvalue = *intptr; The undefined behavior happens as the pointer...