Mariadb проверить ограничение с подзапросом на текущей таблице

Question

Можно ли выполнить проверку ограничения с помощью подзапроса к таблице базы данных maria следующим образом:

CREATE TABLE `tbl` (
  `id` int NOT NULL,
  `start` datetime NOT NULL,
  `end` datetime NOT NULL,
   CONSTRAINT C1 CHECK (id not in (select id from tbl as tt where tt.start between start and end or tt.end between start and end)),
   CONSTRAINT C2 CHECK (end>start)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Я получил ошибку: ОШИБКА 1146 (42S02): Таблица 'test.tbl' не существует

Answer 1

Вы пытаетесь получить доступ к объекту, который не существует (Таблица 'tbl'), вы пытаетесь создать его:

MariaDB [_]> DROP TABLE IF EXISTS `tbl`;
Query OK, 0 rows affected (0.01 sec)

MariaDB [_]> CREATE TABLE IF NOT EXISTS `tbl` (
    ->   `id` INT NOT NULL,
    ->   `start` DATETIME NOT NULL,
    ->   `end` DATETIME NOT NULL,
    ->   CONSTRAINT `C1` CHECK (`id` NOT IN
    ->             (SELECT `id`
    ->              FROM `tbl` AS `tt`
    ->              WHERE `tt`.`start` BETWEEN `start` AND `end` OR
    ->                    `tt`.`end` BETWEEN `start` AND `end`)
    ->   ),
    ->   CONSTRAINT `C2` CHECK (`end` > `start`)
    -> );
ERROR 1146 (42S02): Table '_.tbl' doesn't exist

В случае доступа к объекту, который существует:

MariaDB [_]> DROP TABLE IF EXISTS `tbl_TEMP`, `tbl`;
Query OK, 0 rows affected, 2 warnings (0.00 sec)

MariaDB [_]> CREATE TABLE IF NOT EXISTS `tbl_TEMP` (
    ->   `id` INT NOT NULL,
    ->   `start` DATETIME NOT NULL,
    ->   `end` DATETIME NOT NULL
    -> );
Query OK, 0 rows affected (0.00 sec)

MariaDB [_]> CREATE TABLE IF NOT EXISTS `tbl` (
    ->   `id` INT NOT NULL,
    ->   `start` DATETIME NOT NULL,
    ->   `end` DATETIME NOT NULL,
    ->   CONSTRAINT `C1` CHECK (
    ->     `id` NOT IN (SELECT `id`
    ->                  FROM `tbl_TEMP` AS `tt`
    ->                  WHERE `tt`.`start` BETWEEN `start` AND `end` OR
    ->                        `tt`.`end` BETWEEN `start` AND `end`)
    ->   ),
    ->   CONSTRAINT `C2` CHECK (`end` > `start`)
    -> );
ERROR 1901 (HY000): Function or expression 'select ...'
                    cannot be used in the CHECK clause of `C1`

Опция, которая может быть полезна:

MariaDB [_]> DROP TABLE IF EXISTS `tbl`;
Query OK, 0 rows affected, 1 warning (0.00 sec)

MariaDB [_]> CREATE TABLE IF NOT EXISTS `tbl` (
    ->   `id` INT NOT NULL,
    ->   `start` DATETIME NOT NULL,
    ->   `end` DATETIME NOT NULL,
    ->   CONSTRAINT `C2` CHECK (`end` > `start`)
    -> );
Query OK, 0 rows affected (0.00 sec)

MariaDB [_]> DELIMITER //

MariaDB [_]> CREATE TRIGGER `trg_bi_idduplicate` BEFORE INSERT ON `tbl`
    -> FOR EACH ROW 
    -> BEGIN
    ->       IF EXISTS (SELECT NULL
    ->                  FROM `tbl`
    ->                  WHERE `id` = NEW.`id`) THEN
    ->         SIGNAL SQLSTATE '45000' SET
    ->         MYSQL_ERRNO = 31001,
    ->         MESSAGE_TEXT = '`id` DUPLICATE';
    ->       END IF;
    -> END//
Query OK, 0 rows affected (0.00 sec)

MariaDB [_]> DELIMITER ;

MariaDB [_]> INSERT INTO `tbl`
    -> SELECT 1, '2000-01-01 00:00:01', '2000-01-01 00:00:01';
ERROR 4025 (23000): CONSTRAINT `C2` failed for `_`.`tbl`

MariaDB [_]> INSERT INTO `tbl`
    -> SELECT 1, '2000-01-01 00:00:01', '2000-01-01 00:00:02';
Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

MariaDB [_]> SELECT
    ->   `id`,
    ->   `start`,
    ->   `end`
    -> FROM
    ->   `tbl`;
+----+---------------------+---------------------+
| id | start               | end                 |
+----+---------------------+---------------------+
|  1 | 2000-01-01 00:00:01 | 2000-01-01 00:00:02 |
+----+---------------------+---------------------+
1 row in set (0.00 sec)

MariaDB [_]> INSERT INTO `tbl`
    -> SELECT 1, '2000-01-01 00:00:01', '2000-01-01 00:00:02';
ERROR 31001 (45000): `id` DUPLICATE

MariaDB [_]> SELECT
    ->   `id`,
    ->   `start`,
    ->   `end`
    -> FROM
    ->   `tbl`;
+----+---------------------+---------------------+
| id | start               | end                 |
+----+---------------------+---------------------+
|  1 | 2000-01-01 00:00:01 | 2000-01-01 00:00:02 |
+----+---------------------+---------------------+
1 row in set (0.00 sec)