There are multiple Options available for Drupal Multi-Site installation. Couple of them are listed down here;

• Each site can have its own database
• All the sites can share the same database
• Each site can have own content database & shared user database. This can be done in two different ways either by creating a separate DB for User related tables (or) considering one of the site as a base  &  the hold the user tables in that DB

Approach for single sign-on

If  the option of having different content database for all sites & using one site as base (for User tables) is selected, then the following snippet might help you implementing the solutions. I’m providing snippet (or) information to this implementation because the drupal.org, have solutions for all the other implementation.

Solution :

Step 1: Install & Configure Drupal Multi-Site , remember to setup all the drupal instance with different database.  After the installation is complete you should be having multiple site running with multiple database on one code base

Step 2: As per the  Module developer Guide, Drupal can connect to different databases with elegance and ease.  Please note, it has to be of the same database type. So we convert the $db_url variable to an array.

$db_url['default'] = 'mysql://drupal:drupal@localhost/drupal';
$db_url['base'] = 'mysql://user:pwd@localhost/anotherdb';

now, we need to establish connect to the base database  using the drupal function db_set_active() as & when required.  db_set_active() function can be used to change where database queries are sent. If the database has not yet been used, it is initialized using the URL specified for that name in Drupal’s configuration file. If this name is not defined, a duplicate of the default connection is made instead.Be sure to change the connection back to the default when done with custom code.

db_set_active($name = 'default');

Parameters
$name The name assigned to the newly active database connection. If omitted, the default connection will be made active.
Return value
the name of the previously active database or FALSE if non was found.

Note : This only works with two databases of the same type.

Alternative Implementation of the Solution:

Now there is one challenge of  harding coding the base DB informations, as its not a good practice,because if the DB connection parameter value changes you may need to update multiple place. So to avoid this, you can use the following code snippet.

Base Site’s Setting - Add this line after the $db_url

$db_url=array('default'=>$db_url, 'base'=>$db_url);

Child Site’s Custom Setting – Add the below snippet after your $db_url declaration of the respective child sites.

 // Folder name of the site which you consider as base. Please remember in multi-site environment you are going to have folder for ever site
$dName='example.com';
require_once "sites/$dName/settings.php";
$b_db_url=$db_url['base'];
$db_url=array('default'=>$db_url, 'base'=>$b_db_url);

Some Alternatives : http://drupal.org/project/sso,

This solution will be applicable only if you wish to host the User database on your server, else you can use Open ID authentication

Updated on Jan 07,2010 : This solution can be implemented for the Drupal sites which is running as Separate instance & in the same server (Shared Hosting). Provide the complete path of the BASE Site’s default folder.

For Ex :

[phpull]include_once[/phpull](“/srv/www/sites/www_xyz_com/sites/default/settings.php”);

To make this solution, completely configurable one, please create a variable to hold the Base site folder Name

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1.How can I maintain the count of how many persons have hit my site?
2. What is difference between mysql_fetch_array(), mysql_fetch_row() and mysql_fetch_object()?
3. How I can make a chat page in php in simple
4. What is the difference between echo and print statement?
5. What is differenc between mysql_connect and mysql_pconnect?
6. How I can get IP address of the usr?
7. How I will check that user is logged in or not?
8. I want to make it a function and I want to use it in each page and after login I want to go in current page?
9. How do we know browser properties?
10. If you have to work with dates in the following format: “Tuesday, February 14, 2006 @ 10:39 am”, how can you convert them to another format, that is easier to use?
11. What is difference between require_once(), require(), include()?

Around 9.30 PM IST, i have updated all my file and upgraded my database as well. Upgrading database ?? ya of course as this version of wordpress have some new features there are some new tables which needs to be created. The two main new feature which i was pretty impressed with are inbuilt TAGS & plugin and core update notification. What is it all about.

Tags:
many of us would have use ultimate tag warrior plugin to have tagging feature in our blog, so from now there is no need for using any special plugins for this. Its available in the wordpress system by default. This features creates some new tables, i have listed them down:

• wp_term_taxonomy
• wp_term_relationships
• wp_terms

You will have an option in the create post page(post-new.php) for adding your tags. This option is available just below the text area.
The other notable feature is plugin and core update notification.
Its really cool stuff, what these guys are come up with. Usually we you many plugins to enhance our wordpress blog, but most of us are lazy to find out whether the plugin which we are using is latest one. Its not common with every one to update those plugins as soon as a new version is released. From now we don’t have that problem as we are getting a new feature in our wordpress which is nothing but plugin & core updates. This particular feature will display a notification message when ever there is a update available for that plugin

Right now i have not tested the beta release as the whole. Let me check it and update you more on features & bugs.

Bug Updates:

• The only minus point is that my current theme is not compatible with wordpress 2.3 beta-1.
• When you add Tag’s using the inbuilt options, they are getting store in the database, when you return to the editing mode of that particular post, nothing is showing up. . It needs a fix immediately

Apart from these two services used by wordpress, i ping some other services which i have listed below. Some of you might be interested in these services. Here is the list of blog pinging services:

http://api.feedster.com/ping

http://api.moreover.com/ping

http://api.my.yahoo.com/rss/ping

http://blogsearch.google.com/ping/RPC2

http://ping.amagle.com/

http://ping.bitacoras.com

http://ping.blo.gs/

http://ping.feedburner.com

http://ping.rootblog.com/rpc.php

http://ping.syndic8.com/xmlrpc.php

http://ping.weblogalot.com/rpc.php

http://rcs.datashed.net/RPC2/

http://rpc.blogbuzzmachine.com/RPC2

http://rpc.blogrolling.com/pinger/

http://rpc.icerocket.com:10080/

http://rpc.newsgator.com/

http://rpc.weblogs.com/RPC2

http://topicexchange.com/RPC2

http://www.blogdigger.com/RPC2

http://www.blogoole.com/ping/

http://www.blogoon.net/ping/

http://www.blogsnow.com/ping

http://www.blogstreet.com/xrbin/xmlrpc.cgi

http://www.lasermemory.com/lsrpc/

http://www.newsisfree.com/RPCCloud

http://www.popdex.com/addsite.php

http://www.snipsnap.org/RPC2

http://www.wasalive.com/ping/

http://www.weblogues.com/RPC/

A file with all these url is available for download. You can download it here

Apart from these two services used by wordpress, i ping some other services which i have listed below. Some of you might be interested in these services. Here is the list of blog pinging services:

http://api.feedster.com/ping

http://api.moreover.com/ping

http://api.my.yahoo.com/rss/ping

http://blogsearch.google.com/ping/RPC2

http://ping.amagle.com/

http://ping.bitacoras.com

http://ping.blo.gs/

http://ping.feedburner.com

http://ping.rootblog.com/rpc.php

http://ping.syndic8.com/xmlrpc.php

http://ping.weblogalot.com/rpc.php

http://rcs.datashed.net/RPC2/

http://rpc.blogbuzzmachine.com/RPC2

http://rpc.blogrolling.com/pinger/

http://rpc.icerocket.com:10080/

http://rpc.newsgator.com/

http://rpc.weblogs.com/RPC2

http://topicexchange.com/RPC2

http://www.blogdigger.com/RPC2

http://www.blogoole.com/ping/

http://www.blogoon.net/ping/

http://www.blogsnow.com/ping

http://www.blogstreet.com/xrbin/xmlrpc.cgi

http://www.lasermemory.com/lsrpc/

http://www.newsisfree.com/RPCCloud

http://www.popdex.com/addsite.php

http://www.snipsnap.org/RPC2

http://www.wasalive.com/ping/

http://www.weblogues.com/RPC/

A file with all these url is available for download. You can download it here

Some key benefits

• Large installed base of PHP programmers.
• No compiling and linking steps necessary: just code and run.
• Access to the vast range of existing PHP functions and extensions, including databases, graphics, web functions, XML, PDF, and much more.
• A small set of WinBinder functions encapsulates many complex aspects of the Windows API and makes programming for Windows an easy task.
• Provides 100% native Windows classes and controls.
• Interfaces directly to the Window API. This means fast execution, no extra libraries and no installation required.
• Supports both procedural and object-oriented programming models.
• High performance, compares favorably to most scripting languages.
• Produces standalone applications that can be easily installed and removed with no reboot.
• Small footprint. A simple Windows application, complete with the PHP runtime and SQLite extension, is smaller than 700 kB (zipped).
• A database-independent framework allows easy coding (no SQL knowledge is necessary) and smooth integration with the WinBinder code.
• No database server required if using SQLite.
• Does not need to use to the Windows registry, but may use it if necessary.
• More…