Change table engine for MySQL database, issue #41

Small functions to allow developers choose table engines. Works with
MySQL and MySQLi drivers (other ignore it).

system/database/DB_forge.php

@@ -40,6 +40,7 @@ class CI_DB_forge {
 	public $keys		= array();
 	public $primary_keys	= array();
 	public $db_char_set	=	'';
+	public $engine = '';
 
 	public function __construct()
 	{
@@ -164,6 +165,26 @@ public function add_field($field = '')
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * Add engine
+	 *
+	 * @param	string	the table engine
+	 * @return	object
+	 */
+	public function add_engine($engine = '')
+	{
+		if ($engine == '')
+		{
+			show_error('An engine name is required for that operation.');
+		}
+
+		$this->engine = $engine;
+
+		return $this;
+	}
+
+	// --------------------------------------------------------------------
+
 	/**
 	 * Create Table
 	 *
@@ -181,8 +202,22 @@ public function create_table($table = '', $if_not_exists = FALSE)
 		{
 			show_error('Field information is required.');
 		}
-
-		$sql = $this->_create_table($this->db->dbprefix.$table, $this->fields, $this->primary_keys, $this->keys, $if_not_exists);
+
+		if ($this->engine == '')
+		{
+			$sql = $this->_create_table($this->db->dbprefix.$table, $this->fields, $this->primary_keys, $this->keys, $if_not_exists);
+		}
+		else
+		{
+			if (method_exists($this, '_set_table_engine'))
+			{
+				$sql = $this->_create_table($this->db->dbprefix.$table, $this->fields, $this->primary_keys, $this->keys, $if_not_exists, $this->engine);
+			}
+			else
+			{
+				show_error('Your database does not support different engines.');
+			}
+		}
 		$this->_reset();
 		return is_bool($sql) ? $sql : $this->db->query($sql);
 	}
@@ -219,6 +254,34 @@ public function rename_table($table_name, $new_table_name)
 
 		return $this->db->query($this->_rename_table($this->db->dbprefix.$table_name, $this->db->dbprefix.$new_table_name));
 	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Change table engine
+	 *
+	 * @param	string	the table name
+	 * @param	string	the table engine (MyISAM, InnoDb, etc.)
+	 * @return	bool
+	 */
+	public function set_table_engine($table_name, $engine)
+	{
+		if (method_exists($this, '_set_table_engine'))
+		{
+			if ($table_name == '' OR $engine == '')
+			{
+				show_error('A table name is required for that operation.');
+			}
+
+			return $this->db->query($this->_set_table_engine($this->db->dbprefix.$table_name, $engine));
+		}
+		else
+		{
+			log_message('debug', 'Table change engine function does not exist.');
+
+			return FALSE;
+		}
+	}
 
 	// --------------------------------------------------------------------
 
@@ -341,6 +404,7 @@ public function modify_column($table = '', $field = array())
 	protected function _reset()
 	{
 		$this->fields = $this->keys = $this->primary_keys = array();
+		$this->engine = '';
 	}
 
 }

system/database/drivers/mysql/mysql_forge.php

@@ -167,9 +167,10 @@ function _process_fields($fields)
 	 * @param	mixed	primary key(s)
 	 * @param	mixed	key(s)
 	 * @param	boolean	should 'IF NOT EXISTS' be added to the SQL
+	 * @param	string	the table engine
 	 * @return	bool
 	 */
-	function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists, $engine = NULL)
 	{
 		$sql = 'CREATE TABLE ';
 
@@ -207,8 +208,15 @@ function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
 				$sql .= ",\n\tKEY {$key_name} (" . implode(', ', $key) . ")";
 			}
 		}
-
-		$sql .= "\n) DEFAULT CHARACTER SET {$this->db->char_set} COLLATE {$this->db->dbcollat};";
+
+		if (is_null($engine))
+		{
+			$sql .= "\n) DEFAULT CHARACTER SET {$this->db->char_set} COLLATE {$this->db->dbcollat};";
+		}
+		else
+		{
+			$sql .= "\n) ENGINE {$engine} DEFAULT CHARACTER SET {$this->db->char_set} COLLATE {$this->db->dbcollat};";
+		}
 
 		return $sql;
 	}
@@ -278,6 +286,24 @@ function _rename_table($table_name, $new_table_name)
 		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table_name)." RENAME TO ".$this->db->_protect_identifiers($new_table_name);
 		return $sql;
 	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Set engine of a table
+	 *
+	 * Generates a platform-specific query so engine of that a table can be changed
+	 *
+	 * @access	private
+	 * @param	string	the table name
+	 * @param	string	the table engine
+	 * @return	string
+	 */
+	function _set_table_engine($table_name, $engine)
+	{
+		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table_name).' ENGINE '.$engine;
+		return $sql;
+	}
 
 }
 

system/database/drivers/mysqli/mysqli_forge.php

@@ -152,9 +152,10 @@ function _process_fields($fields)
 	 * @param	mixed	primary key(s)
 	 * @param	mixed	key(s)
 	 * @param	boolean	should 'IF NOT EXISTS' be added to the SQL
+	 * @param	string	the table engine
 	 * @return	bool
 	 */
-	function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists, $engine = NULL)
 	{
 		$sql = 'CREATE TABLE ';
 
@@ -192,8 +193,15 @@ function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
 				$sql .= ",\n\tKEY {$key_name} (" . implode(', ', $key) . ")";
 			}
 		}
-
-		$sql .= "\n) DEFAULT CHARACTER SET {$this->db->char_set} COLLATE {$this->db->dbcollat};";
+
+		if (is_null($engine))
+		{
+			$sql .= "\n) DEFAULT CHARACTER SET {$this->db->char_set} COLLATE {$this->db->dbcollat};";
+		}
+		else
+		{
+			$sql .= "\n) ENGINE {$engine} DEFAULT CHARACTER SET {$this->db->char_set} COLLATE {$this->db->dbcollat};";
+		}
 
 		return $sql;
 	}
@@ -263,6 +271,24 @@ function _rename_table($table_name, $new_table_name)
 		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table_name)." RENAME TO ".$this->db->_protect_identifiers($new_table_name);
 		return $sql;
 	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Set engine of a table
+	 *
+	 * Generates a platform-specific query so engine of that a table can be changed
+	 *
+	 * @access	private
+	 * @param	string	the table name
+	 * @param	string	the table engine
+	 * @return	string
+	 */
+	function _set_table_engine($table_name, $engine)
+	{
+		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table_name).' ENGINE '.$engine;
+		return $sql;
+	}
 
 }
 

user_guide_src/source/database/forge.rst

@@ -169,6 +169,17 @@ below is for MySQL.
 	// gives KEY `blog_name_blog_label` (`blog_name`, `blog_label`)
 
 
+Adding table engine
+===================
+
+If you need to pre-define table engine you can simply use function add_engine().
+Make sure the function is placed before create_table() calling.
+
+::
+
+	$this->dbforge->add_engine('MyISAM');
+
+
 Creating a table
 ================
 
@@ -265,4 +276,17 @@ change the name you can add a "name" key into the field defining array.
 		),
 	);
 	$this->dbforge->modify_column('table_name', $fields);
-	// gives ALTER TABLE table_name CHANGE old_name new_name TEXT
+	// gives ALTER TABLE table_name CHANGE old_name new_name TEXT
+	
+
+$this->dbforge->set_table_engine()
+==================================
+
+The set_table_engine() function is used to change current table engine.
+It requires table name and new engine name as parameters.
+
+::
+
+	$this->dbforge->set_table_engine('table_name', 'MyISAM');
+	// This will produce and execute code: ALTER TABLE table_name ENGINE MyISAM
+