Merge upstream branch
diff --git a/system/database/drivers/sqlsrv/sqlsrv_driver.php b/system/database/drivers/sqlsrv/sqlsrv_driver.php
index bb4f009..bfc2ea0 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_driver.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_driver.php
@@ -55,7 +55,7 @@
 	 * used for the count_all() and count_all_results() functions.
 	 */
 	protected $_count_string = 'SELECT COUNT(*) AS ';
-	protected $_random_keyword = ' NEWID()'; // not currently supported
+	protected $_random_keyword = ' NEWID()';
 
 	/**
 	 * Non-persistent database connection
@@ -148,13 +148,8 @@
 	 */
 	public function trans_begin($test_mode = FALSE)
 	{
-		if ( ! $this->trans_enabled)
-		{
-			return TRUE;
-		}
-
 		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}
@@ -162,7 +157,7 @@
 		// Reset the transaction failure flag.
 		// If the $test_mode flag is set to TRUE transactions will be rolled back
 		// even if the queries produce a successful result.
-		$this->_trans_failure = ($test_mode === TRUE) ? TRUE : FALSE;
+		$this->_trans_failure = ($test_mode === TRUE);
 
 		return sqlsrv_begin_transaction($this->conn_id);
 	}
@@ -176,13 +171,8 @@
 	 */
 	public function trans_commit()
 	{
-		if ( ! $this->trans_enabled)
-		{
-			return TRUE;
-		}
-
 		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}
@@ -199,13 +189,8 @@
 	 */
 	public function trans_rollback()
 	{
-		if ( ! $this->trans_enabled)
-		{
-			return TRUE;
-		}
-
 		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}
@@ -296,15 +281,15 @@
 			return 0;
 		}
 
-		$query = $this->query("SELECT COUNT(*) AS numrows FROM " . $this->dbprefix . $table);
+		$query = $this->query('SELECT COUNT(*) AS numrows FROM '.$this->dbprefix.$table);
 		if ($query->num_rows() == 0)
 		{
 			return 0;
 		}
 
-		$row = $query->row();
+		$query = $query->row();
 		$this->_reset_select();
-		return (int) $row->numrows;
+		return (int) $query->numrows;
 	}
 
 	// --------------------------------------------------------------------
@@ -459,9 +444,9 @@
 	 */
 	protected function _update($table, $values, $where)
 	{
-		foreach($values as $key => $val)
+		foreach ($values as $key => $val)
 		{
-			$valstr[] = $key." = ".$val;
+			$valstr[] = $key.' = '.$val;
 		}
 
 		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).' WHERE '.implode(' ', $where);
@@ -481,7 +466,7 @@
 	 */
 	protected function _truncate($table)
 	{
-		return "TRUNCATE ".$table;
+		return 'TRUNCATE '.$table;
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/sqlsrv/sqlsrv_forge.php b/system/database/drivers/sqlsrv/sqlsrv_forge.php
index 0dc7b52..d331f60 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_forge.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_forge.php
@@ -42,7 +42,7 @@
 	 */
 	public function _create_database($name)
 	{
-		return "CREATE DATABASE ".$name;
+		return 'CREATE DATABASE '.$name;
 	}
 
 	// --------------------------------------------------------------------
@@ -51,11 +51,11 @@
 	 * Drop database
 	 *
 	 * @param	string	the database name
-	 * @return	bool
+	 * @return	string
 	 */
 	public function _drop_database($name)
 	{
-		return "DROP DATABASE ".$name;
+		return 'DROP DATABASE '.$name;
 	}
 
 	// --------------------------------------------------------------------
@@ -63,11 +63,12 @@
 	/**
 	 * Drop Table
 	 *
-	 * @return	bool
+	 * @param	string	the table name
+	 * @return	string
 	 */
 	public function _drop_table($table)
 	{
-		return "DROP TABLE ".$this->db->_escape_identifiers($table);
+		return 'DROP TABLE '.$this->db->_escape_identifiers($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -80,7 +81,7 @@
 	 * @param	mixed	primary key(s)
 	 * @param	mixed	key(s)
 	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @return	string
 	 */
 	public function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
 	{
@@ -91,7 +92,7 @@
 			$sql .= 'IF NOT EXISTS ';
 		}
 
-		$sql .= $this->db->_escape_identifiers($table)." (";
+		$sql .= $this->db->_escape_identifiers($table).' (';
 		$current_field_count = 0;
 
 		foreach ($fields as $field => $attributes)
@@ -101,44 +102,19 @@
 			// entered the field information, so we'll simply add it to the list
 			if (is_numeric($field))
 			{
-				$sql .= "\n\t$attributes";
+				$sql .= "\n\t".$attributes;
 			}
 			else
 			{
 				$attributes = array_change_key_case($attributes, CASE_UPPER);
 
-				$sql .= "\n\t".$this->db->protect_identifiers($field);
-
-				$sql .=  ' '.$attributes['TYPE'];
-
-				if (array_key_exists('CONSTRAINT', $attributes))
-				{
-					$sql .= '('.$attributes['CONSTRAINT'].')';
-				}
-
-				if (array_key_exists('UNSIGNED', $attributes) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
-
-				if (array_key_exists('DEFAULT', $attributes))
-				{
-					$sql .= ' DEFAULT \''.$attributes['DEFAULT'].'\'';
-				}
-
-				if (array_key_exists('NULL', $attributes) && $attributes['NULL'] === TRUE)
-				{
-					$sql .= ' NULL';
-				}
-				else
-				{
-					$sql .= ' NOT NULL';
-				}
-
-				if (array_key_exists('AUTO_INCREMENT', $attributes) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
+				$sql .= "\n\t".$this->db->protect_identifiers($field)
+					.' '.$attributes['TYPE']
+					.( ! empty($attributes['CONSTRAINT']) ? '('.$attributes['CONSTRAINT'].')' : '')
+					.(( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE) ? ' UNSIGNED' : '')
+					.(isset($attributes['DEFAULT']) ? ' DEFAULT \''.$attributes['DEFAULT'].'\'' : '')
+					.(( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE) ? ' NULL' : ' NOT NULL')
+					.(( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE) ? ' AUTO_INCREMENT' : '');
 			}
 
 			// don't add a comma on the end of the last field
@@ -150,8 +126,7 @@
 
 		if (count($primary_keys) > 0)
 		{
-			$primary_keys = $this->db->protect_identifiers($primary_keys);
-			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
+			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->protect_identifiers($primary_keys)).')';
 		}
 
 		if (is_array($keys) && count($keys) > 0)
@@ -167,13 +142,11 @@
 					$key = array($this->db->protect_identifiers($key));
 				}
 
-				$sql .= ",\n\tFOREIGN KEY (" . implode(', ', $key) . ")";
+				$sql .= ",\n\tFOREIGN KEY (".implode(', ', $key).')';
 			}
 		}
 
-		$sql .= "\n)";
-
-		return $sql;
+		return $sql."\n)";
 	}
 
 	// --------------------------------------------------------------------
@@ -203,29 +176,10 @@
 			return $sql;
 		}
 
-		$sql .= " $column_definition";
-
-		if ($default_value != '')
-		{
-			$sql .= " DEFAULT \"$default_value\"";
-		}
-
-		if ($null === NULL)
-		{
-			$sql .= ' NULL';
-		}
-		else
-		{
-			$sql .= ' NOT NULL';
-		}
-
-		if ($after_field != '')
-		{
-			return $sql.' AFTER '.$this->db->protect_identifiers($after_field);
-		}
-
-		return $sql;
-
+		return $sql.' '.$column_definition
+			.($default_value != '' ? ' DEFAULT "'.$default_value.'"' : '')
+			.($null === NULL ? ' NULL' : ' NOT NULL')
+			.($after_field != '' ? ' AFTER '.$this->db->protect_identifiers($after_field) : '');
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/sqlsrv/sqlsrv_result.php b/system/database/drivers/sqlsrv/sqlsrv_result.php
index 10d790e..1adce73 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_result.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_result.php
@@ -92,12 +92,12 @@
 		$retval = array();
 		foreach (sqlsrv_field_metadata($this->result_id) as $offset => $field)
 		{
-			$F 				= new stdClass();
-			$F->name 		= $field['Name'];
-			$F->type 		= $field['Type'];
+			$F 		= new stdClass();
+			$F->name 	= $field['Name'];
+			$F->type 	= $field['Type'];
 			$F->max_length	= $field['Size'];
 			$F->primary_key = 0;
-			$F->default		= '';
+			$F->default	= '';
 
 			$retval[] = $F;
 		}
diff --git a/system/database/drivers/sqlsrv/sqlsrv_utility.php b/system/database/drivers/sqlsrv/sqlsrv_utility.php
index 5830c62..2ef6b24 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_utility.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_utility.php
@@ -41,7 +41,7 @@
 	 */
 	public function _list_databases()
 	{
-		return "EXEC sp_helpdb"; // Can also be: EXEC sp_databases
+		return 'EXEC sp_helpdb'; // Can also be: EXEC sp_databases
 	}
 
 	// --------------------------------------------------------------------
@@ -52,11 +52,11 @@
 	 * Generates a platform-specific query so that a table can be optimized
 	 *
 	 * @param	string	the table name
-	 * @return	bool
+	 * @return	string
 	 */
 	public function _optimize_table($table)
 	{
-		return FALSE; // Is this supported in MS SQL?
+		return 'ALTER INDEX all ON '.$this->db->protect_identifiers($table).' REORGANIZE';
 	}
 
 	// --------------------------------------------------------------------
@@ -71,7 +71,8 @@
 	 */
 	public function _repair_table($table)
 	{
-		return FALSE; // Is this supported in MS SQL?
+		// Not supported in MSSQL
+		return FALSE;
 	}
 
 	// --------------------------------------------------------------------
@@ -80,7 +81,7 @@
 	 * MSSQL Export
 	 *
 	 * @param	array	Preferences
-	 * @return	mixed
+	 * @return	bool
 	 */
 	public function _backup($params = array())
 	{