Tutorial by Examples: e

Consider Kotlin's Null Type system and WeakReference<T>. So let's say we have to save some sort of reference and we wanted to avoid memory leaks, here is where WeakReference comes in. take for example this: class MyMemoryExpensiveClass { companion object { var reference: WeakR...

Using Intents to Load the Image from Gallery. Initially you need to have the permission <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/> Use the Following Code to have the layout as designed follows. <?xml version="1.0" enco...

<?php defined('BASEPATH') OR exit('No direct script access allowed'); class Api extends CI_Controller { //default value private $login_credential; function __construct() { parent::__construct(); //for user authentication $this->load->library('session'); ...

/***************************** @return all events ****************************/ public function getallevents(){ //get data from model $events = array( array('Event 1', '2015-04-03'), array('Event 2', '2015-04-03'), array('Event 3', '2015-06-16'), array('Event 4', '2015-0...

/***************************** login user @required : username and password via post method only @return user data if login successfull otherwise error message ****************************/ public function login(){ $username=$this->input->post('username'); $password=$this->input-...

/*************************** log out user ***************************/ public function logout(){ //delete all session session_destroy(); $this->output->set_output(json_encode(array('status'=>true,'msg'=>'log Out successfully'))); }

This API not accessible for public user, authentication is required /*************************** this is protected api this is not accessible if you are not loged in ***************************/ public function protectedapi(){ if($this->session->userdata('logged_in')){ //this secti...

ng-repeat is the built-in directive provided by AngularJS, mostly used for listing the array elements on UI dynamically as per the changes in our model. Official "ng-repeat" docs can be found at : https://docs.angularjs.org/api/ng/directive/ngRepeat Also the most common error faced whil...

There are times when the framework's Random() class may not be considered random enough, given that it is based on a psuedo-random number generator. The framework's Crypto classes do, however, provide something more robust in the form of RNGCryptoServiceProvider. The following code samples demonstr...

Suppose you have an E-commerce cloud having various Microservices as shopping cart service, Order service, Inventory service and so on. You need to have an API gateway as an Edge service to the outer world. The API gateway abstracts the details(host & port) about the underline Microservices. ...

Let's say a user wants to select data from different tables. A table is specified by the user. function get_value(p_table_name varchar2, p_id number) return varchar2 is value varchar2(100); begin execute immediate 'select column_value from ' || p_table_name || ...

Example below inserts value into the table from the previous example: declare query_text varchar2(1000) := 'insert into my_table(id, column_value) values (:P_ID, :P_VAL)'; id number := 2; value varchar2(100) := 'Bonjour!'; begin execute immediate query_text using id, value; end; / ...

Let's update table from the first example: declare query_text varchar2(1000) := 'update my_table set column_value = :P_VAL where id = :P_ID'; id number := 2; value varchar2(100) := 'Bonjour le monde!'; begin execute immediate query_text using value, id; end; /

This code creates the table: begin execute immediate 'create table my_table (id number, column_value varchar2(100))'; end; /

You can execute anonymous block. This example shows also how to return value from dynamic SQL: declare query_text varchar2(1000) := 'begin :P_OUT := cos(:P_IN); end;'; in_value number := 0; out_value number; begin execute immediate query_text using out out_value, in in_value; dbms_o...

It's very easy to install nedb. npm install nedb --save # Put latest version in your package.json For bower loving people, bower install nedb

While building electron apps, usually the backend is in separate folder (js files) and front end is in a separate folder (html files). In the backend, in order to use the database, we have to include the nedb package with the require statement as follows. var Datastore = require('nedb'),db = new Da...

Basically, in order to insert records to nedb, the data is stored in the form of json with the key being the column names and the value for those names will be the values for that record. var rec = { name: 'bigbounty',age:16}; db.insert(rec, function (err, newrec) { // Callback is optional ...

In order to search for records in nedb, again we need to just pass the json containing the search criteria as a parameter to the find function of db object. db.find({ name: 'bigbounty' }, function (err, docs) { // docs is an array containing documents that have name as bigbounty // If no docu...

In order to remove documents in nedb, it's very easy. We just have to use remove function of db object. db.remove({ name: 'bigbounty' }, function (err, numremoved) { // numremoved is the number of documents that are removed. });