Added and documented Active Record caching.

Made AR fully database-prefix aware

10 files changed, 373 insertions, 48 deletions

diff --git a/system/database/DB_active_rec.php b/system/database/DB_active_rec.php
index e93b99e3d..b3bf02a8b 100644
--- a/system/database/DB_active_rec.php
+++ b/system/database/DB_active_rec.php
@@ -43,6 +43,23 @@ class CI_DB_active_record extends CI_DB_driver {
 	var $ar_set			= array();	

 	var $ar_wherein		= array();

 	var $ar_aliased_tables		= array();

+	var $ar_store_array	= array();

+

+	// Active Record Caching variables

+	var $ar_caching 		= FALSE;

+	var $ar_cache_select	= array();

+	var $ar_cache_from		= array();

+	var $ar_cache_join		= array();

+	var $ar_cache_where		= array();

+	var $ar_cache_like		= array();

+	var $ar_cache_groupby	= array();

+	var $ar_cache_having	= array();

+	var $ar_cache_limit		= FALSE;

+	var $ar_cache_offset	= FALSE;

+	var $ar_cache_order		= FALSE;

+	var $ar_cache_orderby	= array();

+	var $ar_cache_set		= array();	

+

 

 	/**

 	 * DB Prefix

@@ -87,12 +104,23 @@ class CI_DB_active_record extends CI_DB_driver {
 

 			if ($val != '*' && $protect_identifiers !== FALSE)

 			{

-				$val = $this->_protect_identifiers($val);

+				if (strpos($val, '.') !== FALSE)

+				{

+					$val = $this->dbprefix.$val;

+				}

+				else

+				{

+					$val = $this->_protect_identifiers($val);

+				}

 			}

 		

 			if ($val != '')

 			{

 				$this->ar_select[] = $val;

+				if ($this->ar_caching === TRUE)

+				{

+					$this->ar_cache_select[] = $val;

+				}

 			}

 		}

 		return $this;

@@ -122,6 +150,10 @@ class CI_DB_active_record extends CI_DB_driver {
 		$sql = 'MAX('.$this->_protect_identifiers(trim($select)).') AS '.$this->_protect_identifiers(trim($alias));

 

 		$this->ar_select[] = $sql;

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_select[] = $sql;

+		}

 		

 		return $this;

 	}

@@ -150,7 +182,11 @@ class CI_DB_active_record extends CI_DB_driver {
 		$sql = 'MIN('.$this->_protect_identifiers(trim($select)).') AS '.$this->_protect_identifiers(trim($alias));

 

 		$this->ar_select[] = $sql;

-		

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_select[] = $sql;

+		}

+

 		return $this;

 	}

 

@@ -178,7 +214,11 @@ class CI_DB_active_record extends CI_DB_driver {
 		$sql = 'AVG('.$this->_protect_identifiers(trim($select)).') AS '.$this->_protect_identifiers(trim($alias));

 

 		$this->ar_select[] = $sql;

-		

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_select[] = $sql;

+		}

+

 		return $this;

 	}

 

@@ -206,7 +246,11 @@ class CI_DB_active_record extends CI_DB_driver {
 		$sql = 'SUM('.$this->_protect_identifiers(trim($select)).') AS '.$this->_protect_identifiers(trim($alias));

 

 		$this->ar_select[] = $sql;

-		

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_select[] = $sql;

+		}

+

 		return $this;

 	}

 

@@ -243,6 +287,10 @@ class CI_DB_active_record extends CI_DB_driver {
 		foreach ((array)$from as $val)

 		{

 			$this->ar_from[] = $this->_protect_identifiers($this->_track_aliases($val));

+			if ($this->ar_caching === TRUE)

+			{

+				$this->ar_cache_from[] = $this->_protect_identifiers($val);

+			}

 		}

 

 		return $this;

@@ -289,7 +337,14 @@ class CI_DB_active_record extends CI_DB_driver {
 			$cond = preg_replace('|([\w\.]+)([\W\s]+)(.+)|', $this->dbprefix . "$1$2" . $this->dbprefix . "$3", $cond);

 		}	

 

-		$this->ar_join[] = $type.'JOIN '.$this->_protect_identifiers($this->dbprefix.$table, TRUE).' ON '.$cond;

+		$join = $type.'JOIN '.$this->_protect_identifiers($this->dbprefix.$table, TRUE).' ON '.$cond;

+

+		$this->ar_join[] = $join;

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_join[] = $join;

+		}

+

 		return $this;

 	}

 	

@@ -360,7 +415,7 @@ class CI_DB_active_record extends CI_DB_driver {
 		{

 			$key = array($key => $value);

 		}

- 	 	

+

 		foreach ($key as $k => $v)

 		{

 			$prefix = (count($this->ar_where) == 0) ? '' : $type;

@@ -393,10 +448,18 @@ class CI_DB_active_record extends CI_DB_driver {
 				}

 			

 				$v = ' '.$this->escape($v);

-

 			}

-						

+			else

+			{

+				$k = $this->_protect_identifiers($k, TRUE);

+			}

+

 			$this->ar_where[] = $prefix.$k.$v;

+			if ($this->ar_caching === TRUE)

+			{

+				$this->ar_cache_where[] = $prefix.$k.$v;

+			}

+			

 		}

 		return $this;

 	}

@@ -507,7 +570,13 @@ class CI_DB_active_record extends CI_DB_driver {
 

 		$prefix = (count($this->ar_where) == 0) ? '' : $type;

  	 			

-		$this->ar_where[] = $prefix . $this->_protect_identifiers($key) . $not . " IN (" . implode(", ", $this->ar_wherein) . ") ";

+		$where_in = $prefix . $this->_protect_identifiers($key) . $not . " IN (" . implode(", ", $this->ar_wherein) . ") ";

+

+		$this->ar_where[] = $where_in;

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_where[] = $where_in;

+		}

 

 		// reset the array for multiple calls

 		$this->ar_wherein = array();

@@ -629,16 +698,23 @@ class CI_DB_active_record extends CI_DB_driver {
 

 			if ($side == 'before')

 			{

-				$this->ar_like[] = $prefix." $k $not LIKE '%{$v}'";

+				$like_statement = $prefix." $k $not LIKE '%{$v}'";

 			}

 			elseif ($side == 'after')

 			{

-				$this->ar_like[] = $prefix." $k $not LIKE '{$v}%'";

+				$like_statement = $prefix." $k $not LIKE '{$v}%'";

 			}

 			else

 			{

-				$this->ar_like[] = $prefix." $k $not LIKE '%{$v}%'";

+				$like_statement = $prefix." $k $not LIKE '%{$v}%'";

 			}

+			

+			$this->ar_like[] = $like_statement;

+			if ($this->ar_caching === TRUE)

+			{

+				$this->ar_cache_like[] = $like_statement;

+			}

+			

 		}

 		return $this;

 	}

@@ -664,7 +740,13 @@ class CI_DB_active_record extends CI_DB_driver {
 			$val = trim($val);

 		

 			if ($val != '')

+			{

 				$this->ar_groupby[] = $this->_protect_identifiers($val);

+				if ($this->ar_caching === TRUE)

+				{

+					$this->ar_cache_groupby[] = $this->_protect_identifiers($val);

+				}

+			}

 		}

 		return $this;

 	}

@@ -724,6 +806,7 @@ class CI_DB_active_record extends CI_DB_driver {
 	 *

 	 * @access	private

 	 * @param	string

+

 	 * @param	string

 	 * @return	object

 	 */

@@ -737,14 +820,20 @@ class CI_DB_active_record extends CI_DB_driver {
 		foreach ($key as $k => $v)

 		{

 			$prefix = (count($this->ar_having) == 0) ? '' : $type;

+			$k = $this->_protect_identifiers($k);

 			

 			if ($v != '')

 			{

-				$v = ' '.$this->escape($v);

+				$v = ' '.$this->escape_str($v);

 			}

 			

 			$this->ar_having[] = $prefix.$k.$v;

+			if ($this->ar_caching === TRUE)

+			{

+				$this->ar_cache_having[] = $prefix.$k.$v;

+			}

 		}

+		

 		return $this;

 	}

 	

@@ -770,7 +859,14 @@ class CI_DB_active_record extends CI_DB_driver {
 			$direction = (in_array(strtoupper(trim($direction)), array('ASC', 'DESC'), TRUE)) ? ' '.$direction : ' ASC';

 		}

 		

-		$this->ar_orderby[] = $this->_protect_identifiers($orderby, TRUE).$direction;

+		$orderby_statement = $this->_protect_identifiers($orderby, TRUE).$direction;

+		

+		$this->ar_orderby[] = $orderby_statement;

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_orderby[] = $orderby_statement;

+		}

+

 		return $this;

 	}

 	

@@ -799,9 +895,19 @@ class CI_DB_active_record extends CI_DB_driver {
 	function limit($value, $offset = '')

 	{

 		$this->ar_limit = $value;

-		

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_limit[] = $value;

+		}

+

 		if ($offset != '')

+		{

 			$this->ar_offset = $offset;

+			if ($this->ar_caching === TRUE)

+			{

+				$this->ar_cache_offset[] = $offset;

+			}

+		}

 		

 		return $this;

 	}

@@ -815,9 +921,14 @@ class CI_DB_active_record extends CI_DB_driver {
 	 * @param	integer	the offset value

 	 * @return	object

 	 */

-	function offset($value)

+	function offset($offset)

 	{

-		$this->ar_offset = $value;

+		$this->ar_offset = $offset;

+		if ($this->ar_caching === TRUE)

+		{

+			$this->ar_cache_offset[] = $offset;

+		}

+			

 		return $this;

 	}

 	

@@ -846,12 +957,19 @@ class CI_DB_active_record extends CI_DB_driver {
 			if ($escape === FALSE)

 			{

 				$this->ar_set[$this->_protect_identifiers($k)] = $v;

+				if ($this->ar_caching === TRUE)

+				{

+					$this->ar_cache_offset[$this->_protect_identifiers($k)] = $v;

+				}

 			}

 			else

 			{

 				$this->ar_set[$this->_protect_identifiers($k)] = $this->escape($v);

+				if ($this->ar_caching === TRUE)

+				{

+					$this->ar_cache_offset[$this->_protect_identifiers($k)] = $this->escape($v);

+				}

 			}

-

 		}

 		

 		return $this;

@@ -1331,6 +1449,11 @@ class CI_DB_active_record extends CI_DB_driver {
 	 */

 	function _compile_select($select_override = FALSE)

 	{

+		if ($this->ar_caching === TRUE)

+		{

+			$this->_merge_cache();

+		}

+

 		$sql = ( ! $this->ar_distinct) ? 'SELECT ' : 'SELECT DISTINCT ';

 	

 		$sql .= (count($this->ar_select) == 0) ? '*' : implode(', ', $this->ar_select);

@@ -1456,6 +1579,107 @@ class CI_DB_active_record extends CI_DB_driver {
 	// --------------------------------------------------------------------

 

 	/**

+	 * Start Cache

+	 *

+	 * Starts AR caching

+	 *

+	 * @access	public

+	 * @return	void

+	 */		

+	function start_cache()

+	{

+		$this->ar_caching = TRUE;

+	}

+

+	// --------------------------------------------------------------------

+

+	/**

+	 * Stop Cache

+	 *

+	 * Stops AR caching

+	 *

+	 * @access	public

+	 * @return	void

+	 */		

+	function stop_cache()

+	{

+		$this->ar_caching = FALSE;

+	}

+

+

+	// --------------------------------------------------------------------

+

+	/**

+	 * Flush Cache

+	 *

+	 * Empties the AR cache

+	 *

+	 * @access	public

+	 * @return	void

+	 */	

+	function flush_cache()

+	{	

+		$ar_reset_items = array(

+			'ar_cache_select' => array(), 

+			'ar_cache_from' => array(), 

+			'ar_cache_join' => array(),

+			'ar_cache_where' => array(), 

+			'ar_cache_like' => array(), 

+			'ar_cache_groupby' => array(), 

+			'ar_cache_having' =>array(), 

+			'ar_cache_orderby' => array(), 

+			'ar_cache_set' => array()

+		);

+

+		$this->_reset_run($ar_reset_items);	

+	}

+

+	// --------------------------------------------------------------------

+

+	/**

+	 * Merge Cache

+	 *

+	 * When called, this function merges any cached AR arrays with 

+	 * locally called ones.

+	 *

+	 * @access	private

+	 * @return	void

+	 */

+	function _merge_cache()

+	{

+		$ar_items = array('select', 'from', 'join', 'where', 'like', 'groupby', 'having', 'orderby', 'set');

+

+		foreach ($ar_items as $ar_item)

+		{

+			$ar_cache_item = 'ar_cache_'.$ar_item;

+			$ar_item = 'ar_'.$ar_item;

+			$this->$ar_item = array_unique(array_merge($this->$ar_item, $this->$ar_cache_item));

+		}

+	}

+

+	// --------------------------------------------------------------------

+

+	/**

+	 * Resets the active record values.  Called by the get() function

+	 *

+	 * @access	private

+	 * @param	array	An array of fields to reset

+	 * @return	void

+	 */

+	function _reset_run($ar_reset_items)

+	{

+		foreach ($ar_reset_items as $item => $default_value)

+		{

+			if (!in_array($item, $this->ar_store_array))

+			{

+				$this->$item = $default_value;

+			}

+		}

+	}

+	

+	// --------------------------------------------------------------------

+

+	/**

 	 * Resets the active record values.  Called by the get() function

 	 *

 	 * @access	private

@@ -1463,20 +1687,24 @@ class CI_DB_active_record extends CI_DB_driver {
 	 */

 	function _reset_select()

 	{

-		$this->ar_select	= array();

-		$this->ar_distinct	= FALSE;

-		$this->ar_from		= array();

-		$this->ar_join		= array();

-		$this->ar_where		= array();

-		$this->ar_like		= array();

-		$this->ar_groupby	= array();

-		$this->ar_having	= array();

-		$this->ar_limit		= FALSE;

-		$this->ar_offset	= FALSE;

-		$this->ar_order		= FALSE;

-		$this->ar_orderby	= array();

-		$this->ar_wherein	= array();

-		$this->ar_aliased_tables = array();

+		$ar_reset_items = array(

+			'ar_select' => array(), 

+			'ar_from' => array(), 

+			'ar_join' => array(), 

+			'ar_where' => array(), 

+			'ar_like' => array(), 

+			'ar_groupby' => array(), 

+			'ar_having' => array(), 

+			'ar_orderby' => array(), 

+			'ar_wherein' => array(), 

+			'ar_aliased_tables' => array(),

+			'ar_distinct' => FALSE, 

+			'ar_limit' => FALSE, 

+			'ar_offset' => FALSE, 

+			'ar_order' => FALSE,

+		);

+		

+		$this->_reset_run($ar_reset_items);

 	}

 	

 	// --------------------------------------------------------------------

@@ -1490,16 +1718,19 @@ class CI_DB_active_record extends CI_DB_driver {
 	 * @return	void

 	 */

 	function _reset_write()

-	{

-		$this->ar_set		= array();

-		$this->ar_from		= array();

-		$this->ar_where		= array();

-		$this->ar_like		= array();

-		$this->ar_limit		= FALSE;

-		$this->ar_order		= FALSE;

-		$this->ar_orderby	= array();

+	{	

+		$ar_reset_items = array(

+			'ar_set' => array(), 

+			'ar_from' => array(), 

+			'ar_where' => array(), 

+			'ar_like' => array(),

+			'ar_orderby' => array(), 

+			'ar_limit' => FALSE, 

+			'ar_order' => FALSE

+		);

+

+		$this->_reset_run($ar_reset_items);

 	}

 	

 }

-

 ?>
\ No newline at end of file
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index ad747d4ad..ecd404b52 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -433,6 +433,13 @@ class CI_DB_mssql_driver extends CI_DB {
 	function _protect_identifiers($item, $affect_spaces = TRUE, $first_word_only = FALSE)

 	{

 		// MSSQL doesn't use backticks

+		if (strpos($item, '.') !== FALSE)

+		{

+			$aliased_tables = implode(".",$this->ar_aliased_tables).'.';

+			$table_name =  substr($item, 0, strpos($item, '.')+1);

+			$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;

+		}

+

 		return $item;

 	}

 			

diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index f00257250..a5082d1b3 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -454,6 +454,13 @@ class CI_DB_mysql_driver extends CI_DB {
 		// we may need "`item1` `item2`" and not "`item1 item2`"

 		if (ctype_alnum($item) === FALSE)

 		{

+			if (strpos($item, '.') !== FALSE)

+			{

+				$aliased_tables = implode(".",$this->ar_aliased_tables).'.';

+				$table_name =  substr($item, 0, strpos($item, '.')+1);

+				$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;

+			}

+

 			// This function may get "field >= 1", and need it to return "`field` >= 1"

 			$lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';

 

diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index b2e97f927..9e7cc0c9f 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -448,6 +448,13 @@ class CI_DB_mysqli_driver extends CI_DB {
 		// we may need "`item1` `item2`" and not "`item1 item2`"

 		if (ctype_alnum($item) === FALSE)

 		{

+			if (strpos($item, '.') !== FALSE)

+			{

+				$aliased_tables = implode(".",$this->ar_aliased_tables).'.';

+				$table_name =  substr($item, 0, strpos($item, '.')+1);

+				$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;

+			}

+

 			// This function may get "field >= 1", and need it to return "`field` >= 1"

 			$lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';

 

diff --git a/system/database/drivers/oci8/oci8_driver.php b/system/database/drivers/oci8/oci8_driver.php
index ddc0fba99..aa2aeca42 100644
--- a/system/database/drivers/oci8/oci8_driver.php
+++ b/system/database/drivers/oci8/oci8_driver.php
@@ -559,6 +559,13 @@ class CI_DB_oci8_driver extends CI_DB {
 		// we may need "`item1` `item2`" and not "`item1 item2`"

 		if (ctype_alnum($item) === FALSE)

 		{

+			if (strpos($item, '.') !== FALSE)

+			{

+				$aliased_tables = implode(".",$this->ar_aliased_tables).'.';

+				$table_name =  substr($item, 0, strpos($item, '.')+1);

+				$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;

+			}

+

 			// This function may get "field >= 1", and need it to return "`field` >= 1"

 			$lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';

 

diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index 03c0e6a86..88fff4365 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -424,6 +424,13 @@ class CI_DB_odbc_driver extends CI_DB {
 		// we may need "`item1` `item2`" and not "`item1 item2`"

 		if (ctype_alnum($item) === FALSE)

 		{

+			if (strpos($item, '.') !== FALSE)

+			{

+				$aliased_tables = implode(".",$this->ar_aliased_tables).'.';

+				$table_name =  substr($item, 0, strpos($item, '.')+1);

+				$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;

+			}

+

 			// This function may get "field >= 1", and need it to return "`field` >= 1"

 			$lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';

 

diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index e72981348..ae8bd86eb 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -444,6 +444,13 @@ class CI_DB_postgre_driver extends CI_DB {
 		// we may need ""item1" "item2"" and not ""item1 item2""

 		if (ctype_alnum($item) === FALSE)

 		{

+			if (strpos($item, '.') !== FALSE)

+			{

+				$aliased_tables = implode(".",$this->ar_aliased_tables).'.';

+				$table_name =  substr($item, 0, strpos($item, '.')+1);

+				$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;

+			}

+

 			// This function may get "field >= 1", and need it to return ""field" >= 1"

 			$lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';

 

@@ -486,7 +493,7 @@ class CI_DB_postgre_driver extends CI_DB {
 			$tables = array($tables);

 		}

 		

-		return implode(', ', $tables);

+		return '('.implode(', ', $tables).')';

 	}

 

 	// --------------------------------------------------------------------

diff --git a/system/database/drivers/sqlite/sqlite_driver.php b/system/database/drivers/sqlite/sqlite_driver.php
index 38febca29..dad5eeedf 100644
--- a/system/database/drivers/sqlite/sqlite_driver.php
+++ b/system/database/drivers/sqlite/sqlite_driver.php
@@ -440,6 +440,13 @@ class CI_DB_sqlite_driver extends CI_DB {
 		// we may need "`item1` `item2`" and not "`item1 item2`"

 		if (ctype_alnum($item) === FALSE)

 		{

+			if (strpos($item, '.') !== FALSE)

+			{

+				$aliased_tables = implode(".",$this->ar_aliased_tables).'.';

+				$table_name =  substr($item, 0, strpos($item, '.')+1);

+				$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;

+			}

+

 			// This function may get "field >= 1", and need it to return "`field` >= 1"

 			$lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';

 

diff --git a/user_guide/changelog.html b/user_guide/changelog.html
index 1732e505d..573db864f 100644
--- a/user_guide/changelog.html
+++ b/user_guide/changelog.html
@@ -62,10 +62,24 @@ Change Log
 <p>Release Date: -- still in development</p>

 

 <ul>

-	<li>Modified xss_clean() to be more intelligent with its handling of URL encoded strings.</li>

-</ul>

+	<li>Active Record 

+	    <ul>

+	        <li>Added <a href="./database/active_record.html#caching">Active Record Caching</a>.</li>

+	        <li>Made Active Record fully database-prefix aware</li>

+	    </ul>

+	</li>

+    <li>Core Changes

+        <ul>

+            <li>Modified xss_clean() to be more intelligent with its handling of URL encoded strings.</li>

+            </ul>

+    </li>

+    </ul>

 

 

+<h3>Bugfixes for 1.6.1</h3>

+<ul>

+    <li> Made Active Record fully database prefix aware (#3384)</li>

+</ul>

 <h2>Version 1.6.0</h2>

 <p>Release Date: January 30, 2008 </p>

 <ul>

diff --git a/user_guide/database/active_record.html b/user_guide/database/active_record.html
index 12c59e14b..9a75992fa 100644
--- a/user_guide/database/active_record.html
+++ b/user_guide/database/active_record.html
@@ -78,6 +78,7 @@ is generated by each database adapter.  It also allows for safer queries, since
 <li><a href="#update">Updating Data</a></li>

 <li><a href="#delete">Deleting Data</a></li>

 <li><a href="#chaining">Method Chaining</a></li>

+<li><a href="#caching">Active Record Caching</a></li>

 </ul>

 

 

@@ -698,8 +699,8 @@ $this-&gt;db-&gt;truncate('mytable'); <br />
 // TRUNCATE mytable <br />

 </code>

 <p class="important"><strong>Note:</strong> If the TRUNCATE command isn't available, truncate() will execute as &quot;DELETE FROM table&quot;.</p>

-<a name="chaining">&nbsp;</a>

-<h1>Method Chaining</h1>

+

+<h1><a name="chaining">&nbsp;</a>Method Chaining</h1>

 

 <p>Method chaining allows you to simplify your syntax by connecting multiple functions.  Consider this example:</p>

 

@@ -710,8 +711,38 @@ $query = $this->db->get();</code>
 

 <p class="important"><strong>Note:</strong> Method chaining only works with PHP 5.</p>

 

-

-

+<p>&nbsp;</p>

+

+<h1><a name="caching">&nbsp;</a>Active Record Caching</h1>

+<p>While not &quot;true&quot; caching, Active Record enables you to save (or &quot;cache&quot;) certain parts of your queries for reuse later. Normally, when an Active Record call is completed, all stored information is reset for the next call. With caching, you can prevent this reset, and reuse information easily.</p>

+<p>Cached calls are cumulative.  If you makes 2 cached select() calls, and  then 2 uncached select() calls, this will result in 4 select() calls. There are three Caching functions available:</p>

+<h2>$this-&gt;db-&gt;start_cache()</h2>

+<p>This function must be called to begin caching. All Active Record queries of the correct type (see below for supported queries) are stored for later use.</p>

+<h2>$this-&gt;db-&gt;stop_cache()</h2>

+<p>This function can be called to stop caching.</p>

+<h2>$this-&gt;db-&gt;flush_cache()</h2>

+<p>This function deletes all items from the Active Record cache.</p>

+<p>Here's a usage example:</p>

+<p><code> $this-&gt;db-&gt;start_cache();<br />

+    $this-&gt;db-&gt;select('field1');<br />

+    $this-&gt;db-&gt;stop_cache();<br />

+    $this-&gt;db-&gt;get('tablename');<br />

+    // Results in:<br />

+    // SELECT `field1` FROM (`tablename`)<br />

+    <br />

+    this-&gt;db-&gt;select('field2');<br />

+    $this-&gt;db-&gt;get('tablename');<br />

+    // Results in:<br />

+    // SELECT `field1`, `field2` FROM (`tablename`)<br />

+    <br />

+    $this-&gt;db-&gt;flush_cache();<br />

+    <br />

+    this-&gt;db-&gt;select('field2');<br />

+    $this-&gt;db-&gt;get('tablename');<br />

+    // Results in:<br />

+    // SELECT `field2` FROM (`tablename`)</code></p>

+<p class="important"> <strong>Note:</strong> The following fields can be cached: ‘select’, ‘from’, ‘join’, ‘where’, ‘like’, ‘groupby’, ‘having’, ‘orderby’, ‘set’</p>

+<p>&nbsp;</p>

 </div>

 <!-- END CONTENT -->