Title: Sharing user database permission
Last modified: August 31, 2016

---

# Sharing user database permission

 *  [nnitramm](https://wordpress.org/support/users/nnitramm/)
 * (@nnitramm)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/)
 * Hi, I have recently setup my second WordPress installation to use user database
   of my first wp installation. I have setup everything correctly and everything
   works, one problem is just that when I try to login to my second website with
   my admin account, I am getting this error: **You do not have sufficient permissions
   to access this page.** I know I should have replaced this line:
 *     ```
       $this->cap_key = $wpdb->prefix . 'capabilities';
       ```
   
 * in my second wordpress installation’s
    wp-includes/capabilities.php with
 *     ```
       if (defined ('CUSTOM_CAPABILITIES_PREFIX')) {
       	$this->cap_key = CUSTOM_CAPABILITIES_PREFIX . 'capabilities';
       	}
       	else {	$this->cap_key = $wpdb->prefix . 'capabilities';
       	}
       ```
   
 * but there is no such line in capabilities.php in the new wordpress version. Any
   ideas what might help? I only found several old tutorials.

Viewing 8 replies - 1 through 8 (of 8 total)

 *  [Bob Cristello](https://wordpress.org/support/users/gntmidnight/)
 * (@gntmidnight)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997029)
 * When you set up the second WordPress installation to point to the same database
   as the first one, did you choose a different table prefix in your wp-config.php
   file before doing the install? This is the line in the wp-config.php that controls
   what the prefix is:
 *     ```
       /**
        * WordPress Database Table prefix.
        *
        * You can have multiple installations in one database if you give each
        * a unique prefix. Only numbers, letters, and underscores please!
        */
       $table_prefix  = 'wp_';
       ```
   
 * While I don’t suggest it, it is possible to run multiple WordPress installs from
   the same database as long as the prefix is different for the two installations.
 *  Thread Starter [nnitramm](https://wordpress.org/support/users/nnitramm/)
 * (@nnitramm)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997032)
 * Yes I did.
 *  Moderator [bcworkz](https://wordpress.org/support/users/bcworkz/)
 * (@bcworkz)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997038)
 * If you use a different DB prefix there is no reason to prefix capabilities because
   they will come from different tables, depending on which installation is used.
   The only reason I see to prefix capabilities is if one were trying to run two
   sites from the same codebase, which seems plain crazy to me, just use the multi-
   site option.
 * Additionally, any solution that requires altering core files is a really bad 
   solution and should be discarded from consideration.
 * Are you truly so restricted with databases that you cannot simply create a new
   database for the new site? Most hosts make available an adequate quota of DBs.
   Combined with the possibility of multi-site installs, I’m not seeing the point.
 *  Thread Starter [nnitramm](https://wordpress.org/support/users/nnitramm/)
 * (@nnitramm)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997047)
 * No, I’m not so restricted, I just wanted to make users sign up on only one site
   and they will be automatically registered on my second site. It works now perfectly,
   I just wanted to know how to fix You do not have sufficient permissions to access
   this page when trying to access admin dashboard on my second site. Can you help
   me, or is there any other possibility to share an user database between two sites
   without having them in one database?
 *  Moderator [bcworkz](https://wordpress.org/support/users/bcworkz/)
 * (@bcworkz)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997058)
 * This situation arises in these forums on a regular basis. Unfortunately I don’t
   know of any comprehensive topic that would set something up for you. There’s 
   a number of approaches, by searching through old topics you might find an approach
   that resonates with you.
 * I would go ahead and have two installations, each with their own separate DB.
   Designate which installation is to be responsible for authenticating logins, 
   I’ll call it the parent. Alter the other installation’s (child’s) authentication
   process to check password hashes contained in the parent’s DB. This way you don’t
   need to be concerned about odd behavior arising from unforeseen DB conflicts.
 * `wp_authenticate_username_password()` is used by default to authenticate users.
   It gets the user’s WP_User object based on the supplied login name with `get_user_by()`.`
   get_user_by()` is a pluggable function, meaning you can override it with your
   own function. The default gets user data from the DB and creates a new WP_User
   object based on it. Your replacement function would simply get the user data 
   from the parent DB instead.
 * You can connect to the parent DB by creating a new object of the `wpdb` class.
   This would work just like the global `$wpdb` object, except it has a different
   name.
 * There are other functions that get user data, so the above fix only addresses
   part of the situation. You’ll need to track down other user functions and ensure
   they all use parent data. Another option would be to mirror the parent user data
   in the child DB. There aren’t too many functions that update the DB. They should
   all have hooks where you can update the child DB when the parent is updated.
 *  Thread Starter [nnitramm](https://wordpress.org/support/users/nnitramm/)
 * (@nnitramm)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997060)
 * You wouldnt by any chance have any tutorial for this?
 *  Thread Starter [nnitramm](https://wordpress.org/support/users/nnitramm/)
 * (@nnitramm)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997072)
 * I figured it out by using [ this tutorial. ](http://hungred.com/how-to/multiple-wordpress-installation-sharing-user-table-touching-wordpress-core/)
 * You need to copy wp_capabilities and rename it ab_capabilities, where ab is the
   prefix of your second WordPress installation. Now you just need to copy the admin
   priviliges from wp_capabilities to ab_capabilities and it all works like a charm.
   The only problem is just that you cannot be logged in on both sites at the same
   time with this admin account.
 * But now I have another problem and that is that when an user who is for example
   subscriber on first wordpress installation comes to second, his user role doesnt
   copy to the second installation and he is an “orphan”.
    Any help with this?
 *  Moderator [bcworkz](https://wordpress.org/support/users/bcworkz/)
 * (@bcworkz)
 * [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997177)
 * Yeah, you actually need to copy the wp_capabilities value in user meta for _all_
   users. And any time a user is created or their role or capability modified, the
   updated value needs to be copied again.
 * If manually copying becomes onerous, the process could be automated by hooking
   appropriate actions. Initially, the existing capabilities still need to be manually
   copied, but then the hooks can take over.
 * The not logged in to both sites rule would apply to all users, which could become
   a problem. I think it may be possible to create some sort of semaphore system
   between the sites; where, should a user try to access the other site while the
   semaphore is “up” for the current site, the other site would only respond with
   a “please log out of my-other-domain.com first” message.

Viewing 8 replies - 1 through 8 (of 8 total)

The topic ‘Sharing user database permission’ is closed to new replies.

## Tags

 * [capabilities](https://wordpress.org/support/topic-tag/capabilities/)
 * [database](https://wordpress.org/support/topic-tag/database/)
 * [permission](https://wordpress.org/support/topic-tag/permission/)
 * [sharing](https://wordpress.org/support/topic-tag/sharing/)
 * [user](https://wordpress.org/support/topic-tag/user/)

 * In: [Hacks](https://wordpress.org/support/forum/plugins-and-hacks/hacks/)
 * 8 replies
 * 3 participants
 * Last reply from: [bcworkz](https://wordpress.org/support/users/bcworkz/)
 * Last activity: [10 years, 5 months ago](https://wordpress.org/support/topic/sharing-user-database-permission/#post-6997177)
 * Status: not resolved

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