- Patch by Adrian: added support for multiple database connections.

CHANGELOG.txt

@@ -7,7 +7,11 @@ Drupal x.x.x, xxxx-xx-xx
 - menu module:
     * made it possible to customize menus.
 - refactored 403 (forbidden) handling and added support for custom 403 pages.
-- added support for RSS ping-notifications of http://technorati.com/.
+- syndication:
+    * added support for RSS ping-notifications of http://technorati.com/.
+- database backend:
+    * added support for mutiple database connections.
+    * refactored the categorization of news items.
 - usability:
     * slightly reorganized navigation menus.
 

includes/conf.php

@@ -11,6 +11,11 @@
 #   That is, the use of ':', '/', '@', '?', '=' and '#', ''', '"',
 #   and so on is likely to confuse the parser; use alpha-numerical
 #   characters instead.
+#
+#   To specify multiple connections to be used in your site (i.e. for
+#   complex custom modules) you can also specify an associative array
+#   of $db_url variables with the 'default' element used until otherwise
+#   requested.
 
 # $db_url = "mysql://user:password@hostname/database";
 # $db_url = "pgsql://user:password@hostname/database";

includes/database.inc

@@ -18,16 +18,53 @@ function db_prefix_tables($sql) {
   return strtr($sql, array("{" => $prefix, "}" => ""));
 }
 
-$db_type = substr($db_url, 0, strpos($db_url, "://"));
 
-if ($db_type == "mysql") {
-  include_once "includes/database.mysql.inc";
-}
-else {
-  include_once "includes/database.pear.inc";
+/**
+* Use the specified database connection for queries. Initialize the connection if it does not already exist,
+* and if no such member exists, a duplicate of the default connection is made.
+* Be very careful to switch the connection back to the default connection, so as to avoid errors. As the $name
+* parameter defaults to 'default', you only need to run db_set_active() without any arguments to use
+* the default database
+*
+* @param $name The named connection specified in the $db_url variable.
+*/
+function db_set_active($name = 'default') {
+  global $db_url;
+  global $active_db;
+  static $db_conns;
+
+  if (!isset($db_conns[$name])) {
+    //Initiate a new connection, using the named db url specified
+    if (is_array($db_url)) {
+      $connect_url = ($db_url[$name]) ? $db_url[$name] : $db_url['default'];
+    }
+    else {
+      $connect_url = $db_url;
+    }
+
+
+    $db_type = substr($connect_url, 0, strpos($connect_url, "://"));
+
+    //TODO : Allow more than one database api to be present. ie: pgsl and mysql
+    if ($db_type == "mysql") {
+      include_once "includes/database.mysql.inc";
+    }
+    else {
+      include_once "includes/database.pear.inc";
+    }
+
+    $db_conns[$name] = db_connect($connect_url);
+
+  }
+  //set the active connection
+  $active_db = $db_conns[$name];
+
+
 }
 
-db_connect($db_url);
+
+// initialize the default db_url
+db_set_active();
 
 
 ?>

includes/database.mysql.inc

@@ -9,9 +9,11 @@ function db_connect($url) {
      $url["host"] = $url["host"] . ":" . $url["port"];
   }
 
-  mysql_connect($url["host"], $url["user"], $url["pass"]) or die(mysql_error());
+  $connection = mysql_connect($url["host"], $url["user"], $url["pass"]) or die(mysql_error());
   mysql_select_db(substr($url["path"], 1)) or die("unable to select database");
 
+  return $connection;
+
   /*
   ** Note that you can change the 'mysql_connect' statement to 'mysql_pconnect'
   ** if you want to use persistent connections.  This is not recommended on
@@ -70,6 +72,7 @@ function db_queryd($query) {
 
 // private
 function _db_query($query, $debug = 0) {
+  global $active_db;
   global $queries;
 
   if (variable_get("dev_query", 0)) {
@@ -77,7 +80,7 @@ function _db_query($query, $debug = 0) {
     $timer = (float)$usec + (float)$sec;
   }
 
-  $result = mysql_query($query);
+  $result = mysql_query($query, $active_db);
 
   if (variable_get("dev_query", 0)) {
     list($usec, $sec) = explode(" ", microtime());

includes/database.pear.inc

@@ -4,8 +4,6 @@
 require_once 'DB.php';
 
 function db_connect($url) {
-  global $db_handle;
-
   $db_handle = DB::connect($url);
 
   if (DB::isError($db_handle)) {
@@ -13,6 +11,8 @@ function db_connect($url) {
   }
 
   $db_handle->setFetchMode(DB_FETCHMODE_ASSOC);
+
+  return $db_handle;
 }
 
 /**
@@ -65,14 +65,14 @@ function db_queryd($query) {
 
 // private
 function _db_query($query, $debug = 0) {
-  global $db_handle, $queries;
+  global $active_db, $queries;
 
   if (variable_get("dev_query", 0)) {
     list($usec, $sec) = explode(" ", microtime());
     $timer = (float)$usec + (float)$sec;
   }
 
-  $result = $db_handle->query($query);
+  $result = $active_db->query($query);
 
   if (variable_get("dev_query", 0)) {
     list($usec, $sec) = explode(" ", microtime());
@@ -119,16 +119,16 @@ function db_result($result, $row = 0) {
 }
 
 function db_error() {
-  global $db_handle;
+  global $active_db;
 
-  return DB::isError($db_handle);
+  return DB::isError($active_db);
 }
 
 function db_next_id($name) {
-  global $db_handle;
+  global $active_db;
 
   $name = db_prefix_tables($name);
-  $result = $db_handle->nextID($name);
+  $result = $active_db->nextID($name);
   if (DB::isError($result)) {
     watchdog("error", "database: ". $result->getMessage() ."\nsequence table: $name");
   }
@@ -138,9 +138,9 @@ function db_next_id($name) {
 }
 
 function db_affected_rows() {
-  global $db_handle;
+  global $active_db;
 
-  return $db_handle->affectedRows();
+  return $active_db->affectedRows();
 }
 
 /**
@@ -153,7 +153,7 @@ function db_affected_rows() {
  * @return a DB_Result object or a DB_Error
  */
 function db_query_range($query) {
-  global $db_handle, $queries;
+  global $active_db, $queries;
 
   if (variable_get("dev_query", 0)) {
     list($usec, $sec) = explode(" ", microtime());
@@ -167,12 +167,12 @@ function db_query_range($query) {
     $args = array_map("check_query", $args);
     $query = db_prefix_tables($query);
     $args[0] = $query;
-    $result = $db_handle->limitQuery(call_user_func_array("sprintf", $args), $from, $count);
+    $result = $active_db->limitQuery(call_user_func_array("sprintf", $args), $from, $count);
   }
   else {
     $query = func_get_arg(0);
     $query = db_prefix_tables($query);
-    $result = $db_handle->limitQuery( $query, $from, $count);
+    $result = $active_db->limitQuery( $query, $from, $count);
   }
 
   if (variable_get("dev_query", 0)) {