PHP implementation of infinite classification tree (recursion and Optimization)

One 、 Requirements describe

Interface function description ：

Query the complete domestic administrative division information , All provinces 、 All prefecture level cities under the province 、 All districts and counties under prefecture level cities , All data is returned only id、admincode、name、simple_name、lng、lat Six fields .

Two 、 Background Overview

Target table structure ：

CREATE TABLE `lbs_district` (
  `id` char(19) NOT NULL DEFAULT '0' COMMENT '19 position ID',
  `parent_id` char(19) NOT NULL DEFAULT '0' COMMENT ' Of a higher administrative division 19 position ID',
  `name` varchar(100) NOT NULL DEFAULT '' COMMENT ' name ',
  `level` tinyint(1) unsigned NOT NULL DEFAULT '0' COMMENT ' type :1: Countries and regions ,2: Province ,3: Prefecture level cities ,4: District and county ,5: The street ,6: Township 、 other ,7: Noodle business district ,8: Point business district ',
  `level_name` varchar(20) NOT NULL DEFAULT '' COMMENT ' Type the name :1:country,2:province,3:city,4:county,5:town,6:town,7:business,8:business',
  `lng` float(10,6) NOT NULL DEFAULT '0.000000' COMMENT ' Center point  longitude, Longitude coordinates ',
  `lat` float(10,6) NOT NULL DEFAULT '0.000000' COMMENT ' Center point  latitude, Latitude coordinates ',
  `admincode` char(6) NOT NULL DEFAULT '0' COMMENT ' Standard national administrative divisions 6 Bit code ',
  `is_foreign` tinyint(1) unsigned NOT NULL DEFAULT '0' COMMENT ' type :1: Mainland China, Hong Kong and Macao ,2: Taiwan and abroad ',
  `deleted` tinyint(1) NOT NULL DEFAULT '0' COMMENT ' Identify deletion status :0: Don't delete ,1: Delete ',
  `deltime` datetime NOT NULL DEFAULT '0000-00-00 00:00:00' COMMENT ' Delete time ',
  `ctime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ' Creation time ',
  `mtime` datetime NOT NULL DEFAULT '0000-00-00 00:00:00' COMMENT ' Update time ',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT=' Administrative division and business district information table ';

After obtaining the administrative division data from the database , Output Province in tree structure 、 City 、 District and county level administrative division data .

3、 ... and 、 Code implementation

Consider that the data obtained from the library is 3000 multiple , It basically includes the data of the whole country , So it is also possible to consider recursion .

<?php
/**
 * <p>
 *  Interface function description ： Query the complete domestic administrative division information 
 * </p>
 *
 * <p>
 *  Description of data structure of interface output ： Output data to JSON Array form returns , example :
 * <blockquote><pre>
 *              [{
 *                "id":"8008611000000000000",
 *                "parent_id"："8008600000000000000",
 *                "admincode":"110000",
 *                "name":" The Beijing municipal ",
 *                "simple_name":" Beijing ",
 *                "lng":"116.405289",
 *                "lat":"39.904987"
 *              },
 *              {
 *                "id":"8008612010500000000",
 *                "parent_id":"8008600000000000000",
 *                "admincode":"120105",
 *                "name":" Hebei Province ",
 *                "simple_name":" hebei ",
 *                "lng":"117.201569",
 *                "lat":"39.156631"
 *              }]
 * <blockquote><pre>
 * </p>
 *
 * @author bingqing5
 * @date 2022/05/16
 */


header('Content-type: application/json');

require_once 'district_common.php';

/**
 *  Generate tree structure data 
 * @param $items  Processing target data stored as an array 
 * @param $parentId  Parent node ID
 * @return array
 */
function generateTree($items , $parentId)
{
    //  Initializing an array , Used to store output data 
    $tree = array();
    /*  Traversal array , Recursive processing of data */
    foreach($items as $k => $v)
    {

        /*  Judge the status of the current node parentId Whether it is the same as the parameter ？
         *  If the same , Recursion down the same parent node . further 
         *  Judge whether the child nodes of the current node are not empty , If you don't 
         *  It's empty , Put the current node into the current parent node's children in 
         */
        if($v['parent_id'] == $parentId)
        {
            $set = generateTree($items , $v['id']);
            if (!empty($set))
            {
                $v['children'] = generateTree($items , $v['id']);
            }

            $tree[] = $v;
        }
    }
    return $tree;
}


$sql = "
SELECT
	ld.id,
	ld.parent_id,
	ld.admincode,
	ld.name,
	lde.simple_name,
	ld.lng,
	ld.lat,
	ld.level
FROM
	lbs_district ld
	LEFT JOIN lbs_district_extends lde ON ld.id = lde.lbs_district_id
WHERE
    ld.is_foreign = 1
	AND ld.level IN (2,3,4)
	ORDER BY ld.id ASC";



$return = $db->getAll($sql);
//  It is required to obtain the information of domestic province 、 City 、 The tree structure of district and county administrative divisions , Therefore, the root node is the administrative division of China ID
$treeRes = generateTree($return, '8008600000000000000');
echo json_encode($treeRes);;
$db->close();

?>

The above code is due to the internal project environment of the company , It uses PHP5, The recursive part of the code uses PHP7 It can be written like this ：

function generateTree($items , $parentId)
{
    $tree = [];
    foreach($items as $k => $v)
    {

        if($v['parent_id'] == $parentId)
        {
            if (!empty(generateTree($items , $v['id'])))
            {
                $v['childs'] = generateTree($items , $v['id']);
            }

            $tree[] = $v;
        }
    }
    return $tree;
}

Words ,PHP It's really a pit , Author use PHP7 The writing method of "run on the line" , Always reporting mistakes . Because the author's job is Java Development , Yes PHP That's all Greek , It was also undertaken temporarily at the request of the team leader PHP Development tasks , When writing code, it is inevitable to always bring Java Grammar habits of ...

Four 、 Optimize

After submitting the code , Online testing , The result is shown in Fig. ：

  Obviously , The interface needs to get the data 20s, This is an unacceptable thing . after , On this basis, colleagues completed the optimization , The code is as follows ：

<?php
/**
 * <p>
 *  Interface function description ： Query the complete domestic administrative division information 
 * </p>
 *
 * <p>
 *  Description of data structure of interface output ： Output data to JSON Array form returns , example :
 * <blockquote><pre>
 *              [{
 *                "id":"8008611000000000000",
 *                "parent_id"："8008600000000000000",
 *                "admincode":"110000",
 *                "name":" The Beijing municipal ",
 *                "simple_name":" Beijing ",
 *                "lng":"116.405289",
 *                "lat":"39.904987"
 *              },
 *              {
 *                "id":"8008612010500000000",
 *                "parent_id":"8008600000000000000",
 *                "admincode":"120105",
 *                "name":" Hebei Province ",
 *                "simple_name":" hebei ",
 *                "lng":"117.201569",
 *                "lat":"39.156631"
 *              }]
 * <blockquote><pre>
 * </p>
 *
 * @author bingqing5
 * @date 2022/05/16
 */


header('Content-type: application/json');

require_once 'district_common.php';

/**
 *  Generate tree structure data 
 * @param $items  Processing target data stored as an array 
 * @param $parentId  Parent node ID
 * @return array
 */
function generateTree($items , $parentId) {
    //  Initializing an array , Used to store output data 
    $tree = array();
    /*  Traversal array , Recursive processing of data */
    foreach($items as $k => $v) {

        /*  Judge the status of the current node parentId Whether it is the same as the parameter ？
         *  If the same , Recursion down the same parent node . further 
         *  Judge whether the child nodes of the current node are not empty , If you don't 
         *  It's empty , Put the current node into the current parent node's children in 
         */
        if(isset($v['parent_id']) && $v['parent_id'] == $parentId) {
            if($v['level']!=4){// Only provincial and prefecture level cities have child nodes 
                $set = generateTree($items , $v['id']);
                if (!empty($set)) {
                    $v['children'] = generateTree($items , $v['id']);
                }
//            $v['children'] = generateTree($items , $v['id']);
            }
            unset($v['parent_id']);// Fewer output fields , Increase interface speed 
            $tree[] = $v;
        }
    }
    return $tree;
}

// Too much data , Only some basic data is output , Disassociate , Will it be very slow 
/*
$sql = "
SELECT
	ld.id,
	ld.parent_id,
	ld.admincode,
	ld.name,
	lde.simple_name,
	ld.lng,
	ld.lat,
	ld.level
FROM
	lbs_district ld
	LEFT JOIN lbs_district_extends lde ON ld.id = lde.lbs_district_id
WHERE
    ld.is_foreign = 1
	AND ld.level IN (2,3,4)
	ORDER BY ld.id ASC";
*/
$sql = "
SELECT
	ld.id,
	ld.parent_id,
	ld.name,
	ld.lng,
	ld.lat,
	ld.level
FROM
	lbs_district ld
WHERE
    ld.is_foreign = 1
	AND ld.level IN (2,3,4)
	ORDER BY ld.id ASC";

$return = $db->getAll($sql);
//  It is required to obtain the information of domestic province 、 City 、 The tree structure of district and county administrative divisions , Therefore, the root node is the administrative division of China ID
$treeRes = generateTree($return, '8008600000000000000');
echo json_encode($treeRes);;
$db->close();

?>

The response speed of the optimized interface is greatly improved , Pictured ：