Yii: relate n:m on both sides of an AR

问题

For a better user experience, I didn't want to just make a casual PM system, but actually group it into conversations. And as an added feature, being able to PM multiple people at once. Something that was requested multiple times. So I created this:

/*
    User conversations

        ONE Conversation
        HAS MANY Conversation Members
            HAS MANY Users
        HAS MANY Private Messages

        ONE Private Message
        HAS ONE Conversation

        ONE User
        HAS MANY Conversation Member
            HAS ONE Conversation
*/
CREATE TABLE IF NOT EXISTS `tbl_user_pm_conv_members` (
    `user_id` int(11),
    `conv_id` int(11)
);
CREATE TABLE IF NOT EXISTS `tbl_user_pm_conv` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `owner_id` int(11) NOT NULL,
    `subject` varchar(255) NOT NULL,
    PRIMARY KEY (`id`)
);
CREATE TABLE IF NOT EXISTS `tbl_user_pm_msg` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `conv_id` int(11) NOT NULL,
    `from_id` int(11) NOT NULL,
    `body` text NOT NULL,
    `sent` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (`id`)
);

I hope this actually makes sense...

Now, I wanted to setup the n:m relation in Yii (1.1.16 currently). But no matter what I do, it does not want to resolve.

In User.php:

public function relations() {
    return array(
        'profile'=>array(self::HAS_ONE, 'UserProfile', 'uID'),
        'updates'=>array(self::HAS_MANY, "UserUpdate", "tID"),
        'permissions'=>array(self::HAS_MANY, "UserPermissions", "uID"),
        'settings'=>array(self::HAS_ONE, "UserSettings", "id"),
        'convos'=>array(
            self::MANY_MANY, "PrivateConversation",
            "tbl_user_pm_conv_members(id,id)",
        )
    );
}

By Yii's logic, my FKs should probably have been user_id and convo_id, resulting in tbl_user_pm_conv_members(user_id, convo_id). I also do not have MySQL constraints set, as I haven't understood them yet.

When I try to print_r($user->convos), I get this:

2015/04/28 23:49:01 [error] [system.db.CDbCommand] CDbCommand::fetchAll() failed: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'convos_convos.id' in 'on clause'. The SQL statement executed was: SELECT `convos`.`id` AS `t1_c0`, `convos`.`owner_id` AS `t1_c1`, `convos`.`subject` AS `t1_c2` FROM `tbl_user_pm_conv` `convos`  INNER JOIN `tbl_user_pm_conv_members` `convos_convos` ON (`convos_convos`.`id`=:ypl0) AND (`convos`.`id`=`convos_convos`.`id`).
2015/04/28 23:49:01 [error] [exception.CDbException] exception 'CDbException' with message 'CDbCommand failed to execute the SQL statement: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'convos_convos.id' in 'on clause'' in /Users/Ingwie/Work/BIRD3/php_modules/yiisoft/yii/framework/db/CDbCommand.php:543

I am lost. What is the right way to set up the n:m relation?

回答1:

You have an error in:

"tbl_user_pm_conv_members(id,id)",

It should be:

"tbl_user_pm_conv_members(user_id,conv_id)",

来源：https://stackoverflow.com/questions/29931920/yii-relate-nm-on-both-sides-of-an-ar

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