Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Database column information.

 *

 * @package    core_dml

 * @copyright  2008 Petr Skoda (http://skodak.org)

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') || die();

/**

 * Detailed database field information.

 *

 * It is based on the adodb library's ADOFieldObject object.

 * 'column' does mean 'the field' here.

 *

 * @package    core_dml

 * @copyright  2008 Petr Skoda (http://skodak.org)

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 *

 * @property-read string $name Name of column - lowercase.

 * @property-read string $type Driver dependent native data type. Not standardised, it's used to find meta_type.

 *

 * Max length:

 *  character type - number of characters

 *  blob - number of bytes

 *  integer - number of digits

 *  float - digits left from floating point

 *  boolean - 1

 * @property-read int    $max_length size of the database field, eg how much data can you put in there.

 *

 * @property-read int    $scale Scale of field, decimal points (float), null otherwise.

 * @property-read bool   $not_null true if the field is set to NOT NULL.

 * @property-read bool   $primary_key true if the field is the primary key. (usually 'id').

 * @property-read bool   $auto_increment True if field is autoincrementing or sequence.

 * @property-read bool   $binary True if the field is binary.

 * @property-read bool   $has_default True if the default value is defined.

 * @property-read string $default_value The default value (if defined).

 * @property-read bool   $unique True if the field values are unique, false if not.

 *

 * Standardised one character column type, uppercased and enumerated as follows:

 * R - counter (integer primary key)

 * I - integers

 * N - numbers (floats)

 * C - characters and strings

 * X - texts

 * B - binary blobs

 * L - boolean (1 bit)

 * T - timestamp - unsupported

 * D - date - unsupported

 * @property-read string $meta_type Standardised one character column type, uppercased and enumerated: R,I,N,C,X,B,L,T,D

 */

class database_column_info {

    /**

     * @var array The internal storage of column data.

     */

    protected $data;

    /**

     * Magic set function.  This is a read only object and you aren't allowed to write to any variables.

     *

     * @param string $name ignored.

     * @param mixed $value ignored.

     * @throws coding_exception You are not allowed to set data on database_column_info

     */

    public function __set($name, $value) {

        throw new coding_exception('database_column_info is a ready only object to allow for faster caching.');

    }

    /**

     * Magic get function.

     *

     * @param string $variablename variable name to return the value of.

     * @return mixed The variable contents.

     *

     * @throws coding_exception You cannot request a variable that is not allowed.

     */

    public function __get($variablename) {

        if (isset($this->data[$variablename]) || array_key_exists($variablename, $this->data)) {

            return $this->data[$variablename];

        }

        throw new coding_exception('Asked for a variable that is not available . ('.$variablename.').');

    }

    /**

     * Magic isset function.

     *

     * @param string $variablename The name of the property to test if isset().

     * @return bool Whether the value is set or not.

     */

    public function __isset($variablename) {

        return isset($this->data[$variablename]);

    }

    /**

     * Constructor

     *

     * @param mixed $data object or array with properties

     */

    public function __construct($data) {

        // Initialize all the allowed variables to null so the array key exists.

        $validelements = array('name', 'type', 'max_length', 'scale', 'not_null', 'primary_key',

                               'auto_increment', 'binary', 'has_default',  'default_value',

                               'unique', 'meta_type');

        foreach ($validelements as $element) {

            if (isset($data->$element)) {

                $this->data[$element] = $data->$element;

            } else {

                $this->data[$element] = null;

            }

        }

        switch ($this->data['meta_type']) {

            case 'R': // normalise counters (usually 'id')

                $this->data['binary']         = false;

                $this->data['has_default']    = false;

                $this->data['default_value']  = null;

                $this->data['unique']         = true;

                break;

            case 'C':

                $this->data['auto_increment'] = false;

                $this->data['binary']         = false;

                break;

        }

    }

}