Commit f9482497 authored by Andrew Nicols's avatar Andrew Nicols
Browse files

Merge branch 'MDL-69687-master' of https://github.com/sammarshallou/moodle

parents 0f049286 2fe87d95
......@@ -2038,6 +2038,29 @@ abstract class moodle_database {
return $this->delete_records_select($table, $select, $params);
}
/**
* Deletes records from a table using a subquery. The subquery should return a list of values
* in a single column, which match one field from the table being deleted.
*
* The $alias parameter must be set to the name of the single column in your subquery result
* (e.g. if the subquery is 'SELECT id FROM whatever', then it should be 'id'). This is not
* needed on most databases, but MySQL requires it.
*
* (On database where the subquery is inefficient, it is implemented differently.)
*
* @param string $table Table to delete from
* @param string $field Field in table to match
* @param string $alias Name of single column in subquery e.g. 'id'
* @param string $subquery Subquery that will return values of the field to delete
* @param array $params Parameters for subquery
* @throws dml_exception If there is any error
* @since Moodle 3.10
*/
public function delete_records_subquery(string $table, string $field, string $alias,
string $subquery, array $params = []): void {
$this->delete_records_select($table, $field . ' IN (' . $subquery . ')', $params);
}
/**
* Delete one or more records from a table which match a particular WHERE clause.
*
......
......@@ -1688,6 +1688,23 @@ class mysqli_native_moodle_database extends moodle_database {
return true;
}
/**
* Deletes records using a subquery, which is done with a strange DELETE...JOIN syntax in MySQL
* because it performs very badly with normal subqueries.
*
* @param string $table Table to delete from
* @param string $field Field in table to match
* @param string $alias Name of single column in subquery e.g. 'id'
* @param string $subquery Query that will return values of the field to delete
* @param array $params Parameters for query
* @throws dml_exception If there is any error
*/
public function delete_records_subquery(string $table, string $field, string $alias, string $subquery, array $params = []): void {
// Aliases mysql_deltable and mysql_subquery are chosen to be unlikely to conflict.
$this->execute("DELETE mysql_deltable FROM {" . $table . "} mysql_deltable JOIN " .
"($subquery) mysql_subquery ON mysql_subquery.$alias = mysql_deltable.$field", $params);
}
public function sql_cast_char2int($fieldname, $text=false) {
return ' CAST(' . $fieldname . ' AS SIGNED) ';
}
......
......@@ -3491,6 +3491,29 @@ EOD;
$this->assertEquals(1, $DB->count_records($tablename));
}
public function test_delete_records_subquery() {
$DB = $this->tdb;
$dbman = $DB->get_manager();
$table = $this->get_test_table();
$tablename = $table->getName();
$table->add_field('id', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, XMLDB_SEQUENCE, null);
$table->add_field('course', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, '0');
$table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
$dbman->create_table($table);
$DB->insert_record($tablename, array('course' => 3));
$DB->insert_record($tablename, array('course' => 2));
$DB->insert_record($tablename, array('course' => 2));
// This is not a useful scenario for using a subquery, but it will be sufficient for testing.
// Use the 'frog' alias just to make it clearer when we are testing the alias parameter.
$DB->delete_records_subquery($tablename, 'id', 'frog',
'SELECT id AS frog FROM {' . $tablename . '} WHERE course = ?', [2]);
$this->assertEquals(1, $DB->count_records($tablename));
}
public function test_delete_records_list() {
$DB = $this->tdb;
$dbman = $DB->get_manager();
......
......@@ -5327,9 +5327,8 @@ function remove_course_contents($courseid, $showfeedback = true, array $options
// Remove all data from availability and completion tables that is associated
// with course-modules belonging to this course. Note this is done even if the
// features are not enabled now, in case they were enabled previously.
$DB->delete_records_select('course_modules_completion',
'coursemoduleid IN (SELECT id from {course_modules} WHERE course=?)',
array($courseid));
$DB->delete_records_subquery('course_modules_completion', 'coursemoduleid', 'id',
'SELECT id from {course_modules} WHERE course = ?', [$courseid]);
// Remove course-module data that has not been removed in modules' _delete_instance callbacks.
$cms = $DB->get_records('course_modules', array('course' => $course->id));
......
......@@ -56,6 +56,8 @@ information provided here is intended especially for developers.
a callback to be provided to determine whether page can be accessed.
* New setting $CFG->localtempdir overrides which defaults to sys_get_temp_dir()
* Function redirect() now emits a line of backtrace into the X-Redirect-By header when debugging is on
* New DML function $DB->delete_records_subquery() to delete records based on a subquery in a way
that will work across databases.
=== 3.9 ===
* Following function has been deprecated, please use \core\task\manager::run_from_cli().
......
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