在简单情况下,多对多映射很容易在redbean中使用。但是,如何在同一个对象之间进行多个多对多映射?
例子:
我要完成的内容与“关注者”和“关注者”的twitter/instagram设置非常相似
// this c
$user = R::dispense('user');
$user2 = R::dispense('user');
// ..
//Usr1 follows user2
$user->sharedUser[] = $user2;
// user2 follows user1
$user2->sharedUser[] = $user1;
现在,我想从user1的角度列出关注者和后续用户。
但是,如果不查询数据库中的所有用户并寻找user1,就无法列出“关注者”。在这些特殊情况下,有没有办法在Redbean中有多个“共享”列表,或者有什么不错的解决方法,还是查询方式呢?
最佳答案
这是我与测试一起使用以证明其有效的代码:)
<?php
include_once 'rb.php';
R::setup();
//create users
$users = array();
foreach (array('arul', 'jeff', 'mugunth', 'vish') as $name) {
$user = R::dispense('user');
$user->name = $name;
$user->follows = R::dispense('follows');
//create variables with specified names ($arul, $jeff, etc)
$$name = $user;
$users[] = $user;
}
//set relationships
$arul->follows->sharedUser = array($jeff);
$mugunth->follows->sharedUser = array($jeff, $arul);
$vish->follows->sharedUser = array($arul, $mugunth);
R::storeAll($users);
//print relationships
$id = 1;
while (true) {
echo "-----------------------------------\n";
$u = R::load('user', $id++);
if (!$u->id) break;
echo "$u->name follows " . count($u->follows->sharedUser) . " user(s) \n";
if ($u->follows) {
foreach ($u->follows->sharedUser as $f) {
echo " - $f->name \n";
}
}
echo "\n$u->name is followed by "
. R::getCell("SELECT COUNT(*) FROM follows_user WHERE user_id = $u->id")
. " user(s) \n";
foreach ($u->sharedFollows as $f) {
$follower = array_shift($f->ownUser);
echo " - $follower->name \n";
}
}
/* echos the following
-----------------------------------
jeff follows 0 user(s)
jeff is followed by 2 user(s)
- arul
- mugunth
-----------------------------------
arul follows 1 user(s)
- jeff
arul is followed by 2 user(s)
- mugunth
- vish
-----------------------------------
mugunth follows 2 user(s)
- jeff
- arul
mugunth is followed by 1 user(s)
- vish
-----------------------------------
vish follows 2 user(s)
- arul
- mugunth
vish is followed by 0 user(s)
-----------------------------------
*/