original_string: protected function check_user_exists($value, $userfields) {
          global $DB;
  
          $user = null;
          $errorkey = false;
          // The user may use the incorrect field to match the user. This could result in an exception.
          try {
              $field = $userfields['field'];
              // Fields that can be queried in a case-insensitive manner.
              $caseinsensitivefields = [
                  'email',
                  'username',
              ];
              // Build query predicate.
              if (in_array($field, $caseinsensitivefields)) {
                  // Case-insensitive.
                  $select = $DB->sql_equal($field, ':' . $field, false);
              } else {
                  // Exact-value.
                  $select = "{$field} = :{$field}";
              }
  
              // Make sure the record exists and that there's only one matching record found.
              $user = $DB->get_record_select('user', $select, array($userfields['field'] => $value), '*', MUST_EXIST);
          } catch (dml_missing_record_exception $missingex) {
              $errorkey = 'usermappingerror';
          } catch (dml_multiple_records_exception $multiex) {
              $errorkey = 'usermappingerrormultipleusersfound';
          }
          // Field may be fine, but no records were returned.
          if ($errorkey) {
              $usermappingerrorobj = new stdClass();
              $usermappingerrorobj->field = $userfields['label'];
              $usermappingerrorobj->value = $value;
              $this->cleanup_import(get_string($errorkey, 'grades', $usermappingerrorobj));
              unset($usermappingerrorobj);
              return null;
          }
          return $user->id;
      }
code: protected function check_user_exists($value, $userfields) {
          global $DB;
  
          $user = null;
          $errorkey = false;
          // The user may use the incorrect field to match the user. This could result in an exception.
          try {
              $field = $userfields['field'];
              // Fields that can be queried in a case-insensitive manner.
              $caseinsensitivefields = [
                  'email',
                  'username',
              ];
              // Build query predicate.
              if (in_array($field, $caseinsensitivefields)) {
                  // Case-insensitive.
                  $select = $DB->sql_equal($field, ':' . $field, false);
              } else {
                  // Exact-value.
                  $select = "{$field} = :{$field}";
              }
  
              // Make sure the record exists and that there's only one matching record found.
              $user = $DB->get_record_select('user', $select, array($userfields['field'] => $value), '*', MUST_EXIST);
          } catch (dml_missing_record_exception $missingex) {
              $errorkey = 'usermappingerror';
          } catch (dml_multiple_records_exception $multiex) {
              $errorkey = 'usermappingerrormultipleusersfound';
          }
          // Field may be fine, but no records were returned.
          if ($errorkey) {
              $usermappingerrorobj = new stdClass();
              $usermappingerrorobj->field = $userfields['label'];
              $usermappingerrorobj->value = $value;
              $this->cleanup_import(get_string($errorkey, 'grades', $usermappingerrorobj));
              unset($usermappingerrorobj);
              return null;
          }
          return $user->id;
      }
code_tokens: protected function check_user_exists ( $ value , $ userfields ) { global $ DB ; $ user = null ; $ errorkey = false ; // The user may use the incorrect field to match the user. This could result in an exception. try { $ field = $ userfields [ 'field' ] ; // Fields that can be queried in a case-insensitive manner. $ caseinsensitivefields = [ 'email' , 'username' , ] ; // Build query predicate. if ( in_array ( $ field , $ caseinsensitivefields ) ) { // Case-insensitive. $ select = $ DB -> sql_equal ( $ field , ':' . $ field , false ) ; } else { // Exact-value. $ select = "{$field} = :{$field}" ; } // Make sure the record exists and that there's only one matching record found. $ user = $ DB -> get_record_select ( 'user' , $ select , array ( $ userfields [ 'field' ] => $ value ) , '*' , MUST_EXIST ) ; } catch ( dml_missing_record_exception $ missingex ) { $ errorkey = 'usermappingerror' ; } catch ( dml_multiple_records_exception $ multiex ) { $ errorkey = 'usermappingerrormultipleusersfound' ; } // Field may be fine, but no records were returned. if ( $ errorkey ) { $ usermappingerrorobj = new stdClass ( ) ; $ usermappingerrorobj -> field = $ userfields [ 'label' ] ; $ usermappingerrorobj -> value = $ value ; $ this -> cleanup_import ( get_string ( $ errorkey , 'grades' , $ usermappingerrorobj ) ) ; unset ( $ usermappingerrorobj ) ; return null ; } return $ user -> id ; }
docstring: Check that the user is in the system.
  
  @param string $value The value, from the csv file, being mapped to identify the user.
  @param array $userfields Contains the field and label being mapped from.
  @return int Returns the user ID if it exists, otherwise null.
docstring_tokens: Check that the user is in the system .