source: pro-violet-viettel/sourcecode/system/database/drivers/sqlite/sqlite_forge.php

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package             CodeIgniter
 * @author              ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license             http://codeigniter.com/user_guide/license.html
 * @link                http://codeigniter.com
 * @since               Version 1.0
 * @filesource
 */

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

/**
 * SQLite Forge Class
 *
 * @category    Database
 * @author              ExpressionEngine Dev Team
 * @link                http://codeigniter.com/user_guide/database/
 */
class CI_DB_sqlite_forge extends CI_DB_forge {

        /**
         * Create database
         *
         * @access      public
         * @param       string  the database name
         * @return      bool
         */
        function _create_database()
        {
                // In SQLite, a database is created when you connect to the database.
                // We'll return TRUE so that an error isn't generated
                return TRUE;
        }

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

        /**
         * Drop database
         *
         * @access      private
         * @param       string  the database name
         * @return      bool
         */
        function _drop_database($name)
        {
                if ( ! @file_exists($this->db->database) OR ! @unlink($this->db->database))
                {
                        if ($this->db->db_debug)
                        {
                                return $this->db->display_error('db_unable_to_drop');
                        }
                        return FALSE;
                }
                return TRUE;
        }
        // --------------------------------------------------------------------

        /**
         * 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
         * @return      bool
         */
        function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
        {
                $sql = 'CREATE TABLE ';

                // IF NOT EXISTS added to SQLite in 3.3.0
                if ($if_not_exists === TRUE && version_compare($this->db->_version(), '3.3.0', '>=') === TRUE)
                {
                        $sql .= 'IF NOT EXISTS ';
                }

                $sql .= $this->db->_escape_identifiers($table)."(";
                $current_field_count = 0;

                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";
                        }
                        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';
                                }
                        }

                        // don't add a comma on the end of the last field
                        if (++$current_field_count < count($fields))
                        {
                                $sql .= ',';
                        }
                }

                if (count($primary_keys) > 0)
                {
                        $primary_keys = $this->db->_protect_identifiers($primary_keys);
                        $sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
                }

                if (is_array($keys) && count($keys) > 0)
                {
                        foreach ($keys as $key)
                        {
                                if (is_array($key))
                                {
                                        $key = $this->db->_protect_identifiers($key);
                                }
                                else
                                {
                                        $key = array($this->db->_protect_identifiers($key));
                                }

                                $sql .= ",\n\tUNIQUE (" . implode(', ', $key) . ")";
                        }
                }

                $sql .= "\n)";

                return $sql;
        }

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

        /**
         * Drop Table
         *
         *  Unsupported feature in SQLite
         *
         * @access      private
         * @return      bool
         */
        function _drop_table($table)
        {
                if ($this->db->db_debug)
                {
                        return $this->db->display_error('db_unsuported_feature');
                }
                return array();
        }

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

        /**
         * Alter table query
         *
         * 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       string  the field after which we should add the new field
         * @return      object
         */
        function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
        {
                $sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table)." $alter_type ".$this->db->_protect_identifiers($column_name);

                // DROP has everything it needs now.
                if ($alter_type == 'DROP')
                {
                        // SQLite does not support dropping columns
                        // http://www.sqlite.org/omitted.html
                        // http://www.sqlite.org/faq.html#q11
                        return FALSE;
                }

                $sql .= " $column_definition";

                if ($default_value != '')
                {
                        $sql .= " DEFAULT \"$default_value\"";
                }

                if ($null === NULL)
                {
                        $sql .= ' NULL';
                }
                else
                {
                        $sql .= ' NOT NULL';
                }

                if ($after_field != '')
                {
                        $sql .= ' AFTER ' . $this->db->_protect_identifiers($after_field);
                }

                return $sql;

        }

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

        /**
         * Rename a table
         *
         * 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)
        {
                $sql = 'ALTER TABLE '.$this->db->_protect_identifiers($table_name)." RENAME TO ".$this->db->_protect_identifiers($new_table_name);
                return $sql;
        }
}

/* End of file sqlite_forge.php */
/* Location: ./system/database/drivers/sqlite/sqlite_forge.php */