我有一个音乐共享脚本，我正在尝试从我的mysql数据库创建JSON，我正在尝试创建一个特定的结构，似乎无法弄明白
继承我的代码
<?php
//Create Database connection
$db = mysql_connect("localhost","UN","PW");
if (!$db) {
die('Could not connect to db: ' . mysql_error());
}
//Select the Database
mysql_select_db("DB",$db);
$result = mysql_query("SELECT * FROM users ORDER BY username ASC");
$json_response = array(); //Create an array
while ($row = mysql_fetch_array($result))
{
$row_array = array();
$row_array['idu'] = $row['idu'];
$row_array['username'] = $row['username'];
$row_array['first_name'] = $row['first_name'];
$row_array['last_name'] = $row['last_name'];
$row_array['country'] = $row['country'];
$row_array['image'] = $row['image'];
$row_array['cover'] = $row['cover'];
$row_array['description'] = $row['description'];
$row_array['playlists'] = array();
$row_array['tracks'] = array();
$plid = $row['idu'];
$option_qry = mysql_query("SELECT * FROM playlists where playlists.by=$plid");
while ($opt_fet = mysql_fetch_array($option_qry))
{
$row_array['playlists'][] = array(
'id' => $opt_fet['id'],
'name' => $opt_fet['name'],
'by' => $opt_fet['by'],
);
}
array_push($json_response, $row_array); //push the values in the array
//tracks
$option_qry = mysql_query("SELECT * FROM tracks where tracks.uid=$plid");
while ($opt_fet = mysql_fetch_array($option_qry))
{
$row_array['tracks'][] = array(
'id' => $opt_fet['id'],
'title' => $opt_fet['title'],
'name' => $opt_fet['name'],
'art' => $opt_fet['art'],
'likes' => $opt_fet['likes'],
'downloads' => $opt_fet['downloads'],
'plays' => $opt_fet['views'],
'uid' => $opt_fet['uid'],
);
}
array_push($json_response, $row_array); //push the values in the array
}
echo json_encode($json_response,JSON_PRETTY_PRINT);
?>
用户表：
id username last_name first_name country etc...
1 username1 Mynce George USA etc...
2 username2 Jenkins Fred USA etc...
3 username3 Walberg Mark USA etc...
4 username4 Smith Will USA etc...
播放列表表：
id by name
1 4 My playlists
2 3 Popular Songs
playlistentries表：
id playlists track
12 1 13
13 1 23
14 1 3
15 1 17
16 1 9
12 2 14
13 2 24
14 2 4
15 2 18
16 2 10
跟踪表：
id title name art likes downloads views
1 song_title song1.mp3 art1.png 13 8 55
2 song_title song2.mp3 art2.png 12 10 31
3 song_title song3.mp3 art3.png 7 32 50
4 song_title song4.mp3 art4.png 22 11 1
5 song_title song5.mp3 art5.png 1 28 2
下面的JSON是我想要获得的结构，我希望用户创建的每个播放列表将与该播放列表关联的曲目嵌套在该播放列表下的嵌套数组中用户＆gt;播放列表＆gt;曲目（ user＆gt; playlist1＆gt; t1，t2，t3等...＆amp; user＆gt; playlist2＆gt; t1，t2，t3等...），（T for Track fyi）
我在这里输入了两个播放列表“我们给你赞美”和“我们给你赞美2”例如
问题是：如何使用 PLAYLISTENTRIES 在播放列表中排列/嵌套曲目？我已经在USERS下嵌套了PLAYLISTS但我不知道如何使用PLAYLISTS内部的TRACKS深入一级
{
"idu": "2",
"username": "chicagochurch",
"first_name": "Chicago Christian Center",
"last_name": "",
"country": "United States",
"image": "839674815_146358938_1746691162.png",
"cover": "173157219_1187606488_302826016.jpg",
"description": "This is the official Chicago Church Music page.",
"playlists": [
{
"id": "4",
"name": "We Give You Praise",
"by": "2",
"tracks": [
{
"id": "29",
"title": "01 We Give You Praise",
"name": "1667450919_35711384_1898671201.mp3",
"art": "97020012_1272964020_1490042512.png",
"likes": "1",
"downloads": "1",
"plays": "4",
"uid": "2"
},
{
"id": "30",
"title": "02 Luvudees",
"name": "1361859314_884859216_209326964.mp3",
"art": "1591964284_1156840179_1721104535.png",
"likes": "0",
"downloads": "1",
"plays": "3",
"uid": "2"
},
{
"id": "31",
"title": "03 Mugo Del",
"name": "1366849477_130736941_1367659635.mp3",
"art": "1181156184_556035815_1698596436.png",
"likes": "0",
"downloads": "1",
"plays": "0",
"uid": "2"
},
{
"id": "32",
"title": "04 San Amensa",
"name": "40925819_971317614_1732715256.mp3",
"art": "837149755_251638008_1945445596.png",
"likes": "0",
"downloads": "0",
"plays": "1",
"uid": "2"
},
{
"id": "33",
"title": "05 One True God",
"name": "1201163785_1107025307_1077346045.mp3",
"art": "713651840_1636034922_1247445482.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "34",
"title": "06 Mugo Anav",
"name": "173569477_686122962_117960391.mp3",
"art": "1432749408_578109445_1094716795.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "35",
"title": "07 Hallelujah",
"name": "133051077_70993845_552471086.mp3",
"art": "2040610215_1811023913_383444282.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "36",
"title": "08 Sheppard",
"name": "984429058_1532916377_1375134853.mp3",
"art": "1153269141_143559426_997684622.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "37",
"title": "09 I Love you Lord",
"name": "794115968_1411878888_673035094.mp3",
"art": "1692460167_1433248811_682631716.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "38",
"title": "10 Jesus In The Center",
"name": "202390322_461558278_1271927584.mp3",
"art": "1048499380_362527600_4599069.png",
"likes": "0",
"downloads": "1",
"plays": "0",
"uid": "2"
},
{
"id": "39",
"title": "11 Mugo Luvudeemos",
"name": "274506373_302381815_356651583.mp3",
"art": "1229728795_739090349_686501748.png",
"likes": "0",
"downloads": "1",
"plays": "0",
"uid": "2"
},
{
"id": "40",
"title": "12 Onday Chedo Kud",
"name": "378498031_1470949688_1199351944.mp3",
"art": "308978665_1074723934_419931699.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "41",
"title": "13 The Word",
"name": "956461611_287666310_43661088.mp3",
"art": "1584112229_240532531_977129308.png",
"likes": "1",
"downloads": "4",
"plays": "0",
"uid": "2"
}
]
},
{
"id": "5",
"name": "We Give You Praise 2",
"by": "2",
"tracks": [
{
"id": "29",
"title": "01 We Give You Praise 2",
"name": "1667450919_35711384_1898671201.mp3",
"art": "97020012_1272964020_1490042512.png",
"likes": "1",
"downloads": "1",
"plays": "4",
"uid": "2"
},
{
"id": "30",
"title": "02 Luvudees 2",
"name": "1361859314_884859216_209326964.mp3",
"art": "1591964284_1156840179_1721104535.png",
"likes": "0",
"downloads": "1",
"plays": "3",
"uid": "2"
},
{
"id": "31",
"title": "03 Mugo Del 2",
"name": "1366849477_130736941_1367659635.mp3",
"art": "1181156184_556035815_1698596436.png",
"likes": "0",
"downloads": "1",
"plays": "0",
"uid": "2"
},
{
"id": "32",
"title": "04 San Amensa 2",
"name": "40925819_971317614_1732715256.mp3",
"art": "837149755_251638008_1945445596.png",
"likes": "0",
"downloads": "0",
"plays": "1",
"uid": "2"
},
{
"id": "33",
"title": "05 One True God",
"name": "1201163785_1107025307_1077346045.mp3",
"art": "713651840_1636034922_1247445482.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "34",
"title": "06 Mugo Anav 2",
"name": "173569477_686122962_117960391.mp3",
"art": "1432749408_578109445_1094716795.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "35",
"title": "07 Hallelujah 2",
"name": "133051077_70993845_552471086.mp3",
"art": "2040610215_1811023913_383444282.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "36",
"title": "08 Sheppard 2",
"name": "984429058_1532916377_1375134853.mp3",
"art": "1153269141_143559426_997684622.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "37",
"title": "09 I Love you Lord 2",
"name": "794115968_1411878888_673035094.mp3",
"art": "1692460167_1433248811_682631716.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "38",
"title": "10 Jesus In The Center 2",
"name": "202390322_461558278_1271927584.mp3",
"art": "1048499380_362527600_4599069.png",
"likes": "0",
"downloads": "1",
"plays": "0",
"uid": "2"
},
{
"id": "39",
"title": "11 Mugo Luvudeemos 2",
"name": "274506373_302381815_356651583.mp3",
"art": "1229728795_739090349_686501748.png",
"likes": "0",
"downloads": "1",
"plays": "0",
"uid": "2"
},
{
"id": "40",
"title": "12 Onday Chedo Kud 2",
"name": "378498031_1470949688_1199351944.mp3",
"art": "308978665_1074723934_419931699.png",
"likes": "0",
"downloads": "0",
"plays": "0",
"uid": "2"
},
{
"id": "41",
"title": "13 The Word 2",
"name": "956461611_287666310_43661088.mp3",
"art": "1584112229_240532531_977129308.png",
"likes": "1",
"downloads": "4",
"plays": "0",
"uid": "2"
}
]
}
]
}
正如你在上面的结构中看到的那样，播放列表列出了与它相关的轨道在它自己的嵌套数组中，我确定playlistentries表需要用于此但我不知道如何实现它，对不起所有代码...但感谢您的帮助！
使用“playlistsentries”表是否可能这样做
播放列表1（并列出播放列表的名称和信息）有1,2,3,4,5等曲目，并列出每个曲目的信息？并制作我想要实现的数据结构？
因为playlistentries似乎是将播放列表和曲目连接起来的表格...
我完全迷失了该怎么做...感谢您的帮助
答案 0 :(得分：2)
这一切都从您的查询开始。几乎每当你看到自己运行这样的嵌套查询时，你都应该重新思考你的方法。我建议使用连接在单个查询中查询所有数据，然后将结果集读取到可以轻松序列化为JSON的数据结构中。
以下是我将使用的查询：
SELECT
u.`idu` AS `user_id`,
u.`username` AS `user_name`,
u.`first_name` AS `first_name`,
u.`last_name` AS `last_name`,
u.`country` AS `user_country`,
u.`image` AS `user_image`,
u.`cover` AS `user_cover`,
u.`description` AS `user_description`,
pl.`id` AS `playlist_id`,
pl.`name` AS `playlist_name`,
t.`id` AS `track_id`,
t.`title` AS `track_title`,
t.`name` AS `track_name`,
t.`art` AS `track_art`,
t.`likes` AS `track_likes`,
t.`downloads` AS `track_downloads`,
t.`views` AS `track_plays`
FROM users AS u
INNER JOIN playlists AS pl
ON i.idu = pl.by
INNER JOIN playlistsentries AS ple
ON pl.id = ple.playlists
INNER JOIN tracks AS t
ON ple.track = t.id
ORDER BY `user_id` ASC, `playlist_id` ASC, `track_id` ASC
请注意，我使用字段来消除歧义，因此我们现在清楚地知道我们是使用用户，播放列表还是跟踪级字段。
获取结果集时，您一次迭代一个轨道。我们已经对结果集进行了排序，以便对所有用户，播放列表和曲目进行排序（分组），以便您可以查找当前行值的更改，以确定是否需要为用户和播放列表构建新的更高级别的数据容器。 / p>
实现编写所需数据结构和编码为JSON的示例代码如下所示：
// variable in which to store your results to be serialize
$result_array = array();
// some index and temp variables we will use to build the data structure
$current_user_id = 0;
$user_idx = -1;
$current_playlist_id = 0;
$playlist_idx = -1;
// Your database fetch logic here.
// I have not shown where actual query would be made.
// The query would obviously need to succeed before getting to this code.
// Note that you REALLY should be considering mysqli or PDO here
// instead of deprecated mysql extension.
while($row = /* your DB line fetch here - Consider using mysqli or PDO */) {
// is this a new user?
$user_id = (integer)$row['user_id'];
if($user_id !== $current_user_id) {
// manage our indexes
$current_user_id = $user_id;
$user_idx++;
$playlist_idx = -1;
// start a new object to store data for this user
$user_obj = new stdClass();
// set properties on user from current row
// name these properties whatever you want for final JSON structure
$user_obj->idu = $current_user_id;
$user_obj->username = $row['user_name'];
$user_obj->first_name = $row['first_name'];
$user_obj->last_name = $row['last_name'];
$user_obj->country = $row['user_country'];
$user_obj->image = $row['user_image'];
$user_obj->cover = $row['user_cover'];
$user_obj->description = $row['user_description'];
$user_obj->playlists = array();
// set object in overall result array
$result_array[$user_idx] = $user_obj;
}
// does this playlist already exist for this user?
$playlist_id = (int)$row['playlist_id'];
if($playlist_idx === -1 || $playlist_id !== $current_playlist_id ) {
// manage our indexes
$current_playlist_id = $playlist_id;
$playlist_idx++;
// start a new object to store data for this user
$playlist_obj = new stdClass();
// set properties on playlist from current row
// name these properties whatever you want for final JSON structure
$playlist_obj->id = $current_playlist_id;
$playlist_obj->name = $row['playlist_name'];
$playlist_obj->by = $current_user_id;
$playlist_obj->tracks = array();
// set object in overall result array
$result_array[$user_idx]->playlists[$playlist_idx] = $playlist_obj;
}
// create track object
// we do this for every row
$track_obj = new stdClass();
$track_obj->id = $row['track_id'];
$track_obj->title = $row['track_title'];
$track_obj->name = $row['track_name'];
$track_obj->art = $row['track_art'];
$track_obj->likes = $row['track_likes'];
$track_obj->downloads = $row['track_downloads'];
$track_obj->plays = $row['track_plays'];
$track_obj->uid = $current_user_id;
// set track object in result set
$result_array[$user_idx]->playlists[$playlist_idx]->tracks[] = $track_obj;
}
// serialize to JSON
$result_json = json_encode($result_array);
注意：我不太确定您为每个嵌套级别显示的各种用户ID值之间的差异。如果例如轨道和/或播放列表的用户id表示与当前用户不同的用户，则可能需要修改上述代码。如果是这种情况，则需要将这些字段添加到查询中，并将属性添加到对象中。