Tutorial by Examples: u

Find all elements with a certain attribute

Imagine the following XML: <root> <element foobar="hello_world" /> <element example="this is one!" /> </root> /root/element[@foobar] and will return the <element foobar="hello_world" /> element.

xpath • Finding elements containing specific attributes

Find all elements with a certain attribute value

Imagine the following XML: <root> <element foobar="hello_world" /> <element example="this is one!" /> </root> The following XPath expression: /root/element[@foobar = 'hello_world'] will return the <element foobar="hello_world&quo...

xpath • Finding elements containing specific attributes

Populate only a few fields

If you only want the fields houseNum and street in the address field in the final populated doc, use the populate() function as follows in the above two methods, Person.findOne({_id: req.params.id}) .populate('address', 'houseNum street') .exec(function(err, person) { // do somet...

mongoose • Mongoose Population

Model Validation with Custom Attribute

If the built in attributes are not sufficient to validate your model data, then you can place your validation logic in a class derived from ValidationAttribute. In this example only odd numbers are valid values for a model member. Custom Validation Attribute public class OddNumberAttribute : Valid...

asp.net-core • Models

Basic program for signup

Through this example, it will be explained to divide the node.js code into different modules/folders for better undertandibility. Following this technique makes it easier for other developers to understand the code as he can directly refer to concerned file instead of going through whole code. The m...

Node.js • Good coding style

Attribute Routing in Areas

For using Attribute Routing in areas, registering areas and [RouteArea(...)] definitions are required. In RouteConfig.cs : public class RouteConfig { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); ...

asp.net-mvc • Routing

Error Handling: GET all resources

How do you handle errors, rather then log them to the console? Bad way: Router.route('/') .get((req, res) => { Request.find((err, r) => { if(err){ console.log(err) } else { res.json(r) } }) }) .post((req, res) => { const reque...

Node.js • Restful API Design: Best Practices

Requirements

1-HTTP Server. For example: Apache. Having mod_rewrite is preferred, but by no means required. 2-PHP 5.5.9 or greater (including PHP 7) 3-mbstring PHP extens ion 4-intl PHP extension I usually make an apache and mysql installation on a linuxbox. I can use windows too, however I do not recommen...

cakephp • Getting started with cakephp

Un-pivot a dynamic set of columns based on condition

The following example is a very useful basis when you are trying to convert transaction data to un-pivoted data for BI/reporting reasons, where the dimensions which are to be un-pivoted can have a dynamic set of columns. For our example, we suppose that the raw data table contains employee assessme...

MySQL • Dynamic Un-Pivot Table using Prepared Statement

C# implementation of OpenCL 1.2: number of platforms for an AMD system in 64-bit windows

OpenCL is low level api so it must be implemented in "C space" first. For that, one needs to download header files from Khronos' site. My hardware is AMD and capable of version 1.2, downloading opencl.h cl_platform.h cl.h cl_ext.h cl_egl.h cl_dx9_media_sharing.h cl_d3d10.h c...

opencl • Getting started with opencl

Basic mongodump of local default mongod instance

mongodump --db mydb --gzip --out "mydb.dump.$(date +%F_%R)" This command will dump a bson gzipped archive of your local mongod 'mydb' database to the 'mydb.dump.{timestamp}' directory

MongoDB • Backing up and Restoring Data

Basic mongorestore of local default mongod dump

mongorestore --db mydb mydb.dump.2016-08-27_12:44/mydb --drop --gzip This command will first drop your current 'mydb' database and then restore your gzipped bson dump from the 'mydb mydb.dump.2016-08-27_12:44/mydb' archive dump file.

MongoDB • Backing up and Restoring Data

Get all avatars before Parashurama

XML <Dashavatar> <Avatar name="Matsya"/> <Avatar name="Kurma"/> <Avatar name="Varaha"/> <Avatar name="Narasimha"/> <Avatar name="Vamana"/> <Avatar name="Balabhadra"/> ...