Improve the PostgreSQL database driver
diff --git a/system/database/drivers/postgre/postgre_forge.php b/system/database/drivers/postgre/postgre_forge.php
index 756fd34..5af834b 100644
--- a/system/database/drivers/postgre/postgre_forge.php
+++ b/system/database/drivers/postgre/postgre_forge.php
@@ -1,13 +1,13 @@
-<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP 5.1.6 or newer
  *
  * NOTICE OF LICENSE
- * 
+ *
  * Licensed under the Open Software License version 3.0
- * 
+ *
  * This source file is subject to the Open Software License (OSL 3.0) that is
  * bundled with this package in the files license.txt / license.rst.  It is
  * also available through the world wide web at this URL:
@@ -25,8 +25,6 @@
  * @filesource
  */
 
-// ------------------------------------------------------------------------
-
 /**
  * Postgre Forge Class
  *
@@ -39,13 +37,12 @@
 	/**
 	 * Create database
 	 *
-	 * @access	private
 	 * @param	string	the database name
-	 * @return	bool
+	 * @return	string
 	 */
-	function _create_database($name)
+	public function _create_database($name)
 	{
-		return "CREATE DATABASE ".$name;
+		return 'CREATE DATABASE '.$name;
 	}
 
 	// --------------------------------------------------------------------
@@ -53,44 +50,42 @@
 	/**
 	 * Drop database
 	 *
-	 * @access	private
 	 * @param	string	the database name
-	 * @return	bool
+	 * @return	string
 	 */
-	function _drop_database($name)
+	public function _drop_database($name)
 	{
-		return "DROP DATABASE ".$name;
+		return 'DROP DATABASE '.$name;
 	}
 
 	// --------------------------------------------------------------------
-	
+
 	/**
 	 * Process Fields
 	 *
 	 * @param	mixed	the fields
 	 * @return	string
 	 */
-	function _process_fields($fields, $primary_keys=array())
+	private function _process_fields($fields, $primary_keys = array())
 	{
 		$sql = '';
 		$current_field_count = 0;
 
-		foreach ($fields as $field=>$attributes)
+		foreach ($fields as $field => $attributes)
 		{
 			// Numeric field names aren't allowed in databases, so if the key is
 			// numeric, we know it was assigned by PHP and the developer manually
 			// entered the field information, so we'll simply add it to the list
 			if (is_numeric($field))
 			{
-				$sql .= "\n\t$attributes";
+				$sql .= "\n\t".$attributes;
 			}
 			else
 			{
+				$sql .= "\n\t".$this->db->protect_identifiers($field);
+
 				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->_protect_identifiers($field);
-
-				$is_unsigned = (array_key_exists('UNSIGNED', $attributes) && $attributes['UNSIGNED'] === TRUE);
+				$is_unsigned = ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE);
 
 				// Convert datatypes to be PostgreSQL-compatible
 				switch (strtoupper($attributes['TYPE']))
@@ -122,44 +117,24 @@
 					case 'BLOB':
 						$attributes['TYPE'] = 'BYTEA';
 						break;
+					default:
+						break;
 				}
 
 				// If this is an auto-incrementing primary key, use the serial data type instead
-				if (in_array($field, $primary_keys) && array_key_exists('AUTO_INCREMENT', $attributes) 
-					&& $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' SERIAL';
-				}
-				else
-				{
-					$sql .=  ' '.$attributes['TYPE'];
-				}
+				$sql .= (in_array($field, $primary_keys) && ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
+					? ' SERIAL' : ' '.$attributes['TYPE'];
 
 				// Modified to prevent constraints with integer data types
-				if (array_key_exists('CONSTRAINT', $attributes) && strpos($attributes['TYPE'], 'INT') === false)
+				if ( ! empty($attributes['CONSTRAINT']) && strpos($attributes['TYPE'], 'INT') === FALSE)
 				{
 					$sql .= '('.$attributes['CONSTRAINT'].')';
 				}
 
-				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';
-				}
-
-				// Added new attribute to create unqite fields. Also works with MySQL
-				if (array_key_exists('UNIQUE', $attributes) && $attributes['UNIQUE'] === TRUE)
-				{
-					$sql .= ' UNIQUE';
-				}
+				$sql .= (isset($attributes['DEFAULT']) ? " DEFAULT '".$attributes['DEFAULT']."'" : '')
+					.(( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE) ? ' NULL' : ' NOT NULL')
+					// Added new attribute to create unqite fields. Also works with MySQL
+					.(( ! empty($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE) ? ' UNIQUE' : '');
 			}
 
 			// don't add a comma on the end of the last field
@@ -168,7 +143,7 @@
 				$sql .= ',';
 			}
 		}
-		
+
 		return $sql;
 	}
 
@@ -177,15 +152,14 @@
 	/**
 	 * Create Table
 	 *
-	 * @access	private
 	 * @param	string	the table name
 	 * @param	array	the fields
 	 * @param	mixed	primary key(s)
 	 * @param	mixed	key(s)
-	 * @param	boolean	should 'IF NOT EXISTS' be added to the SQL
+	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
 	 * @return	bool
 	 */
-	function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	public function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
 	{
 		$sql = 'CREATE TABLE ';
 
@@ -198,18 +172,17 @@
 			}
 		}
 
-		$sql .= $this->db->_escape_identifiers($table)." (";
-		$sql .= $this->_process_fields($fields, $primary_keys);
+		$sql .= $this->db->_escape_identifiers($table).' ('.$this->_process_fields($fields, $primary_keys);
 
 		if (count($primary_keys) > 0)
 		{
-			// Something seems to break when passing an array to _protect_identifiers()
+			// Something seems to break when passing an array to protect_identifiers()
 			foreach ($primary_keys as $index => $key)
 			{
-				$primary_keys[$index] = $this->db->_protect_identifiers($key);
+				$primary_keys[$index] = $this->db->protect_identifiers($key);
 			}
 
-			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
+			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $primary_keys).')';
 		}
 
 		$sql .= "\n);";
@@ -220,16 +193,16 @@
 			{
 				if (is_array($key))
 				{
-					$key = $this->db->_protect_identifiers($key);
+					$key = $this->db->protect_identifiers($key);
 				}
 				else
 				{
-					$key = array($this->db->_protect_identifiers($key));
+					$key = array($this->db->protect_identifiers($key));
 				}
 
 				foreach ($key as $field)
 				{
-					$sql .= "CREATE INDEX " . $table . "_" . str_replace(array('"', "'"), '', $field) . "_index ON $table ($field); ";
+					$sql .= 'CREATE INDEX '.$table.'_'.str_replace(array('"', "'"), '', $field).'_index ON '.$table.' ('.$field.'); ';
 				}
 			}
 		}
@@ -241,10 +214,13 @@
 
 	/**
 	 * Drop Table
+	 *
+	 * @param	string	table name
+	 * @return	string
 	 */
-	function _drop_table($table)
+	public function _drop_table($table)
 	{
-		return "DROP TABLE IF EXISTS ".$this->db->_escape_identifiers($table)." CASCADE";
+		return 'DROP TABLE IF EXISTS '.$this->db->_escape_identifiers($table).' CASCADE';
 	}
 
 	// --------------------------------------------------------------------
@@ -255,34 +231,27 @@
 	 * Generates a platform-specific query so that a table can be altered
 	 * Called by add_column(), drop_column(), and column_alter(),
 	 *
-	 * @access	private
 	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
 	 * @param	string	the column name
 	 * @param	string	the table name
 	 * @param	string	the column definition
 	 * @param	string	the default value
-	 * @param	boolean	should 'NOT NULL' be added
+	 * @param	bool	should 'NOT NULL' be added
 	 * @param	string	the field after which we should add the new field
-	 * @return	object
+	 * @return	string
 	 */
- 	function _alter_table($alter_type, $table, $fields, $after_field = '')
+	public function _alter_table($alter_type, $table, $fields, $after_field = '')
  	{
- 		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table)." $alter_type ";
+ 		$sql = 'ALTER TABLE '.$this->db->protect_identifiers($table).' '.$alter_type.' ';
 
  		// DROP has everything it needs now.
- 		if ($alter_type == 'DROP')
+ 		if ($alter_type === 'DROP')
  		{
- 			return $sql.$this->db->_protect_identifiers($fields);
+ 			return $sql.$this->db->protect_identifiers($fields);
  		}
 
- 		$sql .= $this->_process_fields($fields);
-
- 		if ($after_field != '')
- 		{
- 			$sql .= ' AFTER ' . $this->db->_protect_identifiers($after_field);
- 		}
-
- 		return $sql;
+ 		return $sql.$this->_process_fields($fields)
+			.($after_field != '' ? ' AFTER '.$this->db->protect_identifiers($after_field) : '');
  	}
 
 	// --------------------------------------------------------------------
@@ -292,17 +261,16 @@
 	 *
 	 * Generates a platform-specific query so that a table can be renamed
 	 *
-	 * @access	private
 	 * @param	string	the old table name
 	 * @param	string	the new table name
 	 * @return	string
 	 */
-	function _rename_table($table_name, $new_table_name)
+	public function _rename_table($table_name, $new_table_name)
 	{
-		$sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table_name)." RENAME TO ".$this->db->_protect_identifiers($new_table_name);
-		return $sql;
+		return 'ALTER TABLE '.$this->db->protect_identifiers($table_name).' RENAME TO '.$this->db->protect_identifiers($new_table_name);
 	}
+
 }
 
 /* End of file postgre_forge.php */
-/* Location: ./system/database/drivers/postgre/postgre_forge.php */
\ No newline at end of file
+/* Location: ./system/database/drivers/postgre/postgre_forge.php */