MDL-61380 Quiz: Fix url generation in notenoughrandomquestions exception
[moodle.git] / question / engine / bank.php
CommitLineData
d1b7e03d 1<?php
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2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
16
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17/**
18 * More object oriented wrappers around parts of the Moodle question bank.
19 *
20 * In due course, I expect that the question bank will be converted to a
21 * fully object oriented structure, at which point this file can be a
22 * starting point.
23 *
017bc1d9 24 * @package moodlecore
d1b7e03d 25 * @subpackage questionbank
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26 * @copyright 2009 The Open University
27 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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28 */
29
30
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31defined('MOODLE_INTERNAL') || die();
32
1fcf0ca8 33require_once(__DIR__ . '/../type/questiontypebase.php');
c468ce59 34
a17b297d 35
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36/**
37 * This static class provides access to the other question bank.
38 *
39 * It provides functions for managing question types and question definitions.
40 *
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41 * @copyright 2009 The Open University
42 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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43 */
44abstract class question_bank {
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45 // TODO: This limit can be deleted if someday we move all TEXTS to BIG ones. MDL-19603
46 const MAX_SUMMARY_LENGTH = 32000;
c83ed025 47
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48 /** @var array question type name => question_type subclass. */
49 private static $questiontypes = array();
50
51 /** @var array question type name => 1. Records which question definitions have been loaded. */
52 private static $loadedqdefs = array();
53
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54 /** @var boolean nasty hack to allow unit tests to call {@link load_question()}. */
55 private static $testmode = false;
56 private static $testdata = array();
57
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58 private static $questionconfig = null;
59
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60 /**
61 * @var array string => string The standard set of grade options (fractions)
62 * to use when editing questions, in the range 0 to 1 inclusive. Array keys
63 * are string becuase: a) we want grades to exactly 7 d.p., and b. you can't
64 * have float array keys in PHP.
65 * Initialised by {@link ensure_grade_options_initialised()}.
66 */
67 private static $fractionoptions = null;
68 /** @var array string => string The full standard set of (fractions) -1 to 1 inclusive. */
69 private static $fractionoptionsfull = null;
70
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71 /**
72 * @param string $qtypename a question type name, e.g. 'multichoice'.
73 * @return bool whether that question type is installed in this Moodle.
74 */
75 public static function is_qtype_installed($qtypename) {
1c74b260 76 $plugindir = core_component::get_plugin_directory('qtype', $qtypename);
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77 return $plugindir && is_readable($plugindir . '/questiontype.php');
78 }
79
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80 /**
81 * Get the question type class for a particular question type.
82 * @param string $qtypename the question type name. For example 'multichoice' or 'shortanswer'.
f7970e3c 83 * @param bool $mustexist if false, the missing question type is returned when
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84 * the requested question type is not installed.
85 * @return question_type the corresponding question type class.
86 */
87 public static function get_qtype($qtypename, $mustexist = true) {
88 global $CFG;
89 if (isset(self::$questiontypes[$qtypename])) {
90 return self::$questiontypes[$qtypename];
91 }
1c74b260 92 $file = core_component::get_plugin_directory('qtype', $qtypename) . '/questiontype.php';
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93 if (!is_readable($file)) {
94 if ($mustexist || $qtypename == 'missingtype') {
88f0eb15 95 throw new coding_exception('Unknown question type ' . $qtypename);
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96 } else {
97 return self::get_qtype('missingtype');
98 }
99 }
100 include_once($file);
101 $class = 'qtype_' . $qtypename;
f29aeb5a 102 if (!class_exists($class)) {
f4fe3968 103 throw new coding_exception("Class {$class} must be defined in {$file}.");
f29aeb5a 104 }
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105 self::$questiontypes[$qtypename] = new $class();
106 return self::$questiontypes[$qtypename];
107 }
108
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109 /**
110 * Load the question configuration data from config_plugins.
111 * @return object get_config('question') with caching.
112 */
fde4560d 113 public static function get_config() {
f9b0500f 114 if (is_null(self::$questionconfig)) {
fde4560d 115 self::$questionconfig = get_config('question');
f9b0500f 116 }
fde4560d 117 return self::$questionconfig;
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118 }
119
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120 /**
121 * @param string $qtypename the internal name of a question type. For example multichoice.
f7970e3c 122 * @return bool whether users are allowed to create questions of this type.
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123 */
124 public static function qtype_enabled($qtypename) {
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125 $config = self::get_config();
126 $enabledvar = $qtypename . '_disabled';
127 return self::qtype_exists($qtypename) && empty($config->$enabledvar) &&
128 self::get_qtype($qtypename)->menu_name() != '';
129 }
130
131 /**
132 * @param string $qtypename the internal name of a question type. For example multichoice.
f7970e3c 133 * @return bool whether this question type exists.
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134 */
135 public static function qtype_exists($qtypename) {
bd3b3bba 136 return array_key_exists($qtypename, core_component::get_plugin_list('qtype'));
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137 }
138
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139 /**
140 * @param $qtypename the internal name of a question type, for example multichoice.
141 * @return string the human_readable name of this question type, from the language pack.
142 */
143 public static function get_qtype_name($qtypename) {
f9b0500f 144 return self::get_qtype($qtypename)->local_name();
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145 }
146
147 /**
148 * @return array all the installed question types.
149 */
150 public static function get_all_qtypes() {
151 $qtypes = array();
bd3b3bba 152 foreach (core_component::get_plugin_list('qtype') as $plugin => $notused) {
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153 try {
154 $qtypes[$plugin] = self::get_qtype($plugin);
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155 } catch (coding_exception $e) {
156 // Catching coding_exceptions here means that incompatible
157 // question types do not cause the rest of Moodle to break.
f29aeb5a 158 }
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159 }
160 return $qtypes;
161 }
162
f9b0500f 163 /**
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164 * Sort an array of question types according to the order the admin set up,
165 * and then alphabetically for the rest.
166 * @param array qtype->name() => qtype->local_name().
167 * @return array sorted array.
f9b0500f 168 */
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169 public static function sort_qtype_array($qtypes, $config = null) {
170 if (is_null($config)) {
171 $config = self::get_config();
172 }
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173
174 $sortorder = array();
175 $otherqtypes = array();
d649fb02 176 foreach ($qtypes as $name => $localname) {
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177 $sortvar = $name . '_sortorder';
178 if (isset($config->$sortvar)) {
179 $sortorder[$config->$sortvar] = $name;
180 } else {
d649fb02 181 $otherqtypes[$name] = $localname;
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182 }
183 }
184
185 ksort($sortorder);
2f1e464a 186 core_collator::asort($otherqtypes);
f9b0500f 187
d649fb02 188 $sortedqtypes = array();
f9b0500f 189 foreach ($sortorder as $name) {
d649fb02 190 $sortedqtypes[$name] = $qtypes[$name];
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191 }
192 foreach ($otherqtypes as $name => $notused) {
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193 $sortedqtypes[$name] = $qtypes[$name];
194 }
195 return $sortedqtypes;
196 }
197
198 /**
199 * @return array all the question types that users are allowed to create,
200 * sorted into the preferred order set on the admin screen.
201 */
202 public static function get_creatable_qtypes() {
203 $config = self::get_config();
204 $allqtypes = self::get_all_qtypes();
205
206 $qtypenames = array();
207 foreach ($allqtypes as $name => $qtype) {
208 if (self::qtype_enabled($name)) {
209 $qtypenames[$name] = $qtype->local_name();
210 }
211 }
212
213 $qtypenames = self::sort_qtype_array($qtypenames);
214
215 $creatableqtypes = array();
216 foreach ($qtypenames as $name => $notused) {
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217 $creatableqtypes[$name] = $allqtypes[$name];
218 }
a13d4fbd 219 return $creatableqtypes;
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220 }
221
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222 /**
223 * Load the question definition class(es) belonging to a question type. That is,
224 * include_once('/question/type/' . $qtypename . '/question.php'), with a bit
225 * of checking.
226 * @param string $qtypename the question type name. For example 'multichoice' or 'shortanswer'.
227 */
228 public static function load_question_definition_classes($qtypename) {
229 global $CFG;
230 if (isset(self::$loadedqdefs[$qtypename])) {
231 return;
232 }
233 $file = $CFG->dirroot . '/question/type/' . $qtypename . '/question.php';
234 if (!is_readable($file)) {
88f0eb15 235 throw new coding_exception('Unknown question type (no definition) ' . $qtypename);
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236 }
237 include_once($file);
238 self::$loadedqdefs[$qtypename] = 1;
239 }
240
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241 /**
242 * This method needs to be called whenever a question is edited.
243 */
244 public static function notify_question_edited($questionid) {
245 question_finder::get_instance()->uncache_question($questionid);
246 }
247
248 /**
249 * Load a question definition data from the database. The data will be
250 * returned as a plain stdClass object.
251 * @param int $questionid the id of the question to load.
252 * @return object question definition loaded from the database.
253 */
254 public static function load_question_data($questionid) {
255 return question_finder::get_instance()->load_question_data($questionid);
256 }
257
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258 /**
259 * Load a question definition from the database. The object returned
260 * will actually be of an appropriate {@link question_definition} subclass.
f7970e3c 261 * @param int $questionid the id of the question to load.
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262 * @param bool $allowshuffle if false, then any shuffle option on the selected
263 * quetsion is disabled.
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264 * @return question_definition loaded from the database.
265 */
a31689a4 266 public static function load_question($questionid, $allowshuffle = true) {
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267 global $DB;
268
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269 if (self::$testmode) {
270 // Evil, test code in production, but now way round it.
271 return self::return_test_question_data($questionid);
272 }
273
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274 $questiondata = self::load_question_data($questionid);
275
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276 if (!$allowshuffle) {
277 $questiondata->options->shuffleanswers = false;
278 }
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279 return self::make_question($questiondata);
280 }
281
282 /**
283 * Convert the question information loaded with {@link get_question_options()}
284 * to a question_definintion object.
285 * @param object $questiondata raw data loaded from the database.
286 * @return question_definition loaded from the database.
287 */
288 public static function make_question($questiondata) {
289 return self::get_qtype($questiondata->qtype, false)->make_question($questiondata, false);
290 }
291
292 /**
293 * @return question_finder a question finder.
294 */
295 public static function get_finder() {
a560d636 296 return question_finder::get_instance();
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297 if (is_null(self::$questionfinder)) {
298 self::$questionfinder = new question_finder();
299 }
300 return self::$questionfinder;
301 }
302
303 /**
304 * Only to be called from unit tests. Allows {@link load_test_data()} to be used.
305 */
306 public static function start_unit_test() {
307 self::$testmode = true;
308 }
309
310 /**
311 * Only to be called from unit tests. Allows {@link load_test_data()} to be used.
312 */
313 public static function end_unit_test() {
314 self::$testmode = false;
315 self::$testdata = array();
316 }
317
318 private static function return_test_question_data($questionid) {
319 if (!isset(self::$testdata[$questionid])) {
88f0eb15 320 throw new coding_exception('question_bank::return_test_data(' . $questionid .
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321 ') called, but no matching question has been loaded by load_test_data.');
322 }
323 return self::$testdata[$questionid];
324 }
325
326 /**
327 * To be used for unit testing only. Will throw an exception if
328 * {@link start_unit_test()} has not been called first.
329 * @param object $questiondata a question data object to put in the test data store.
330 */
331 public static function load_test_question_data(question_definition $question) {
332 if (!self::$testmode) {
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333 throw new coding_exception('question_bank::load_test_data called when ' .
334 'not in test mode.');
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335 }
336 self::$testdata[$question->id] = $question;
337 }
af2f98ee 338
072db71c 339 protected static function ensure_fraction_options_initialised() {
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340 if (!is_null(self::$fractionoptions)) {
341 return;
342 }
343
344 // define basic array of grades. This list comprises all fractions of the form:
345 // a. p/q for q <= 6, 0 <= p <= q
346 // b. p/10 for 0 <= p <= 10
347 // c. 1/q for 1 <= q <= 10
348 // d. 1/20
349 $rawfractions = array(
350 0.9000000,
351 0.8333333,
352 0.8000000,
353 0.7500000,
354 0.7000000,
355 0.6666667,
356 0.6000000,
357 0.5000000,
358 0.4000000,
359 0.3333333,
360 0.3000000,
361 0.2500000,
362 0.2000000,
363 0.1666667,
364 0.1428571,
365 0.1250000,
366 0.1111111,
367 0.1000000,
368 0.0500000,
369 );
370
371 // Put the None option at the top.
372 self::$fractionoptions = array(
373 '0.0' => get_string('none'),
374 '1.0' => '100%',
375 );
376 self::$fractionoptionsfull = array(
377 '0.0' => get_string('none'),
378 '1.0' => '100%',
379 );
380
381 // The the positive grades in descending order.
382 foreach ($rawfractions as $fraction) {
0a5aa9c6 383 $percentage = format_float(100 * $fraction, 5, true, true) . '%';
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384 self::$fractionoptions["{$fraction}"] = $percentage;
385 self::$fractionoptionsfull["{$fraction}"] = $percentage;
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386 }
387
388 // The the negative grades in descending order.
389 foreach (array_reverse($rawfractions) as $fraction) {
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390 self::$fractionoptionsfull['' . (-$fraction)] =
391 format_float(-100 * $fraction, 5, true, true) . '%';
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392 }
393
394 self::$fractionoptionsfull['-1.0'] = '-100%';
395 }
396
397 /**
398 * @return array string => string The standard set of grade options (fractions)
399 * to use when editing questions, in the range 0 to 1 inclusive. Array keys
400 * are string becuase: a) we want grades to exactly 7 d.p., and b. you can't
401 * have float array keys in PHP.
402 * Initialised by {@link ensure_grade_options_initialised()}.
403 */
404 public static function fraction_options() {
405 self::ensure_fraction_options_initialised();
406 return self::$fractionoptions;
407 }
408
409 /** @return array string => string The full standard set of (fractions) -1 to 1 inclusive. */
410 public static function fraction_options_full() {
411 self::ensure_fraction_options_initialised();
412 return self::$fractionoptionsfull;
413 }
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414
415 /**
416 * Perform scheduled maintenance tasks relating to the question bank.
417 */
418 public static function cron() {
419 global $CFG;
420
421 // Delete any old question preview that got left in the database.
422 require_once($CFG->dirroot . '/question/previewlib.php');
423 question_preview_cron();
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424
425 // Clear older calculated stats from cache.
426 require_once($CFG->dirroot . '/question/engine/statisticslib.php');
427 question_usage_statistics_cron();
2ec325c2 428 }
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429
430 /**
431 * Return a list of the different question types present in the given categories.
432 *
433 * @param array $categories a list of category ids
434 * @return array the list of question types in the categories
435 * @since Moodle 3.1
436 */
437 public static function get_all_question_types_in_categories($categories) {
438 global $DB;
439
440 list($categorysql, $params) = $DB->get_in_or_equal($categories);
441 $sql = "SELECT DISTINCT q.qtype
442 FROM {question} q
443 WHERE q.category $categorysql";
444
445 $qtypes = $DB->get_fieldset_sql($sql, $params);
446 return $qtypes;
447 }
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448}
449
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450
451/**
452 * Class for loading questions according to various criteria.
453 *
454 * @copyright 2009 The Open University
455 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
456 */
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457class question_finder implements cache_data_source {
458 /** @var question_finder the singleton instance of this class. */
459 protected static $questionfinder = null;
460
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461 /**
462 * @return question_finder a question finder.
463 */
464 public static function get_instance() {
465 if (is_null(self::$questionfinder)) {
466 self::$questionfinder = new question_finder();
467 }
468 return self::$questionfinder;
469 }
470
471 /* See cache_data_source::get_instance_for_cache. */
472 public static function get_instance_for_cache(cache_definition $definition) {
473 return self::get_instance();
474 }
475
476 /**
477 * @return get the question definition cache we are using.
478 */
479 protected function get_data_cache() {
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480 // Do not double cache here because it may break cache resetting.
481 return cache::make('core', 'questiondata');
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482 }
483
484 /**
485 * This method needs to be called whenever a question is edited.
486 */
487 public function uncache_question($questionid) {
488 $this->get_data_cache()->delete($questionid);
489 }
490
491 /**
492 * Load a question definition data from the database. The data will be
493 * returned as a plain stdClass object.
494 * @param int $questionid the id of the question to load.
495 * @return object question definition loaded from the database.
496 */
497 public function load_question_data($questionid) {
498 return $this->get_data_cache()->get($questionid);
499 }
500
d1b7e03d 501 /**
bb93fc24 502 * Get the ids of all the questions in a list of categories.
2daffca5 503 * @param array $categoryids either a categoryid, or a comma-separated list
d1b7e03d 504 * category ids, or an array of them.
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505 * @param string $extraconditions extra conditions to AND with the rest of
506 * the where clause. Must use named parameters.
507 * @param array $extraparams any parameters used by $extraconditions.
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508 * @return array questionid => questionid.
509 */
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510 public function get_questions_from_categories($categoryids, $extraconditions,
511 $extraparams = array()) {
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512 global $DB;
513
a2ac2349 514 list($qcsql, $qcparams) = $DB->get_in_or_equal($categoryids, SQL_PARAMS_NAMED, 'qc');
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515
516 if ($extraconditions) {
517 $extraconditions = ' AND (' . $extraconditions . ')';
518 }
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519
520 return $DB->get_records_select_menu('question',
f4fe3968 521 "category {$qcsql}
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522 AND parent = 0
523 AND hidden = 0
f4fe3968 524 {$extraconditions}", $qcparams + $extraparams, '', 'id,id AS id2');
d1b7e03d 525 }
a560d636 526
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527 /**
528 * Get the ids of all the questions in a list of categories, with the number
529 * of times they have already been used in a given set of usages.
530 *
531 * The result array is returned in order of increasing (count previous uses).
532 *
533 * @param array $categoryids an array question_category ids.
534 * @param qubaid_condition $qubaids which question_usages to count previous uses from.
535 * @param string $extraconditions extra conditions to AND with the rest of
536 * the where clause. Must use named parameters.
537 * @param array $extraparams any parameters used by $extraconditions.
538 * @return array questionid => count of number of previous uses.
539 */
540 public function get_questions_from_categories_with_usage_counts($categoryids,
541 qubaid_condition $qubaids, $extraconditions = '', $extraparams = array()) {
542 global $DB;
543
544 list($qcsql, $qcparams) = $DB->get_in_or_equal($categoryids, SQL_PARAMS_NAMED, 'qc');
545
546 if ($extraconditions) {
547 $extraconditions = ' AND (' . $extraconditions . ')';
548 }
549
550 return $DB->get_records_sql_menu("
551 SELECT q.id, (SELECT COUNT(1)
552 FROM " . $qubaids->from_question_attempts('qa') . "
553 WHERE qa.questionid = q.id AND " . $qubaids->where() . "
554 ) AS previous_attempts
555
556 FROM {question} q
557
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558 WHERE q.category {$qcsql}
559 AND q.parent = 0
560 AND q.hidden = 0
561 {$extraconditions}
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562
563 ORDER BY previous_attempts
564 ", $qubaids->from_where_params() + $qcparams + $extraparams);
565 }
566
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567 /* See cache_data_source::load_for_cache. */
568 public function load_for_cache($questionid) {
569 global $DB;
570 $questiondata = $DB->get_record_sql('
571 SELECT q.*, qc.contextid
572 FROM {question} q
573 JOIN {question_categories} qc ON q.category = qc.id
574 WHERE q.id = :id', array('id' => $questionid), MUST_EXIST);
575 get_question_options($questiondata);
576 return $questiondata;
577 }
578
579 /* See cache_data_source::load_many_for_cache. */
580 public function load_many_for_cache(array $questionids) {
581 global $DB;
582 list($idcondition, $params) = $DB->get_in_or_equal($questionids);
583 $questiondata = $DB->get_records_sql('
584 SELECT q.*, qc.contextid
585 FROM {question} q
586 JOIN {question_categories} qc ON q.category = qc.id
587 WHERE q.id ' . $idcondition, $params);
588
589 foreach ($questionids as $id) {
590 if (!array_key_exists($id, $questionids)) {
591 throw new dml_missing_record_exception('question', '', array('id' => $id));
592 }
593 get_question_options($questiondata[$id]);
594 }
595 return $questiondata;
596 }
d1b7e03d 597}