アプリ関連ニュース

ホーム
アプリ関連ニュース

2020年6月29日
技術情報

CDN (Content Delivery Network)

Content delivery networks (CDNs) are the transparent backbone of the Internet in charge of content delivery.

The website delay interval is affected by a number of factors, many of which are specific to a given web page. However, in all cases, the length of the delay is affected by the physical distance between you and that website’s hosting server.

The mission of a CDN is to virtually shorten that physical distance, with the goal of improving the speed and performance of the site.

To minimize the distance between visitors and your website’s server, a CDN stores a cached version of its content in multiple geographic locations (points of presence, or PoP). Each PoP contains a number of caching servers responsible for delivering content to visitors within its proximity.

In essence, CDN places your content in many places at once, providing superior coverage to its users. For example, when someone in Japan accesses your website hosted in the USA. USA, Performed through a local Japan PoP. This is much faster than receiving visitor requests and responses, traversing the entire width between the source and destination.

This is how a CDN works in a nutshell. Then I think you might understand roughly how CDN works.

By Yuuma.

yuuma at 2020年06月29日 11:00:56

2020年6月19日
技術情報

[SQL]年齢による条件抽出

データベースレコードには「生年月日」のカラムがありますが、「年齢」のカラムはありません。そのような場合に年齢によるSQLの条件抽出をおこなうためにはどのようにSQLを組み立てていけばいいのでしょうか。

nishida at 2020年06月19日 10:00:45

2020年6月15日
技術情報

Common Aggregate Functions in SQL

Today I will talk about some common aggregate functions that are widely used in SQL programming language.

Count

if we want to get the count of all records or specific where condition records, we can get by using count function.

SELECT COUNT(column_name) FROM table_name
SELECT COUNT(column_name) FROM table_name WHERE condition;

1 2	SELECT COUNT(column_name) FROM table_name SELECT COUNT(column_name) FROM table_name WHERE condition;

AVG

For average rate calculations, we can use this.

SELECT AVG(column_name) FROM table_name;
SELECT AVG(column_name) FROM table_name WHERE condition;

1 2	SELECT AVG(column_name) FROM table_name; SELECT AVG(column_name) FROM table_name WHERE condition;

SUM

For sum results of all records, we can use this.

SELECT SUM(column_name) FROM table_name 
SELECT SUM(column_name) FROM table_name WHERE condition;

1 2	SELECT SUM(column_name) FROM table_name SELECT SUM(column_name) FROM table_name WHERE condition;

MIN

For specific minimum result of a column, we can use this.

SELECT MIN(column_name) FROM table_name;
SELECT MIN(column_name) FROM table_name WHERE condition;

1 2	SELECT MIN(column_name) FROM table_name; SELECT MIN(column_name) FROM table_name WHERE condition;

Likewise min, we can use max to get maximum result.

SELECT MAX(column_name) FROM table_name;
SELECT MAX(column_name) FROM table_name WHERE condition;

1 2	SELECT MAX(column_name) FROM table_name; SELECT MAX(column_name) FROM table_name WHERE condition;

By Yuuma

yuuma at 2020年06月15日 11:00:24

2020年6月12日
技術情報

[Laravel] ルーティングについて

ルーティングとは「ブラウザで入力されたURL」(リクエストURL)と、Laravelのコントローラを紐付ける方法です。

nishida at 2020年06月12日 10:00:10

2020年6月08日
技術情報

PHP Json

Today I will talk about how to operate Json data in PHP especially using json_encode & json_decode.

So, Lets get started. We have an array like this.

<?php
$months = array("Jan"=>"01","Feb"=>"02","March"=>"03","April"=>"04");
?>

<?php

$months = array("Jan"=>"01","Feb"=>"02","March"=>"03","April"=>"04");

If we want to change that array to json format, we can do like this.

<?php
$months = array("Jan"=>"01","Feb"=>"02","March"=>"03","April"=>"04");

echo json_encode($months);
?>

<?php

$months = array("Jan"=>"01","Feb"=>"02","March"=>"03","April"=>"04");

echo json_encode($months);

So What about decoding, decoding the also similar with encoding.

<?php
$json = '{"Jan":"01","Feb":"02","March":"03","April":"04"}';

//we can treat the decoded data in two ways (object & array)
//treating like an object.
$obj = json_decode($json);
echo $obj->Jan;

// treating like an array
$array = json_decode($json,true);
echo $array['Jan'];
?>

<?php

$json = '{"Jan":"01","Feb":"02","March":"03","April":"04"}';

//we can treat the decoded data in two ways (object & array)

//treating like an object.

$obj = json_decode($json);

echo $obj->Jan;

// treating like an array

$array = json_decode($json,true);

echo $array['Jan'];

The sample concept if you want to loop through the decoded json.

<?php
$json = '{"Jan":"01","Feb":"02","March":"03","April":"04"}';

$array = json_decode($jsonobj, true);

foreach($array as $key => $value) {
  echo $key . " => " . $value . "<br>";
}

<?php

$json = '{"Jan":"01","Feb":"02","March":"03","April":"04"}';

$array = json_decode($jsonobj, true);

foreach($array as $key => $value) {

echo $key . " => " . $value . "<br>";

}

<?php
$json = '{"Jan":"01","Feb":"02","March":"03","April":"04"}';

$obj = json_decode($jsonobj);

foreach($obj as $key => $value) {
  echo $key . " => " . $value . "<br>";
}