Slide 53
Slide 53 text
ツリー管理用のテーブル
ancestor, descendant: 先祖/子孫関係にあるノ
ードの組
path_length: ancestor から descendant まで
の距離(必須ではない)
CREATE TABLE `department_closure_table` (
`ancestor` int(10) unsigned NOT NULL,
`descendant` int(10) unsigned NOT NULL,
`path_length` int(10) unsigned NOT NULL,
PRIMARY KEY (`ancestor`, `descendant`),
FOREIGN KEY (`ancestor`)
REFERENCES `department` (`department_id`)
ON DELETE CASCADE ON UPDATE RESTRICT,
FOREIGN KEY (`descendant`)
REFERENCES `department` (`department_id`)
ON DELETE CASCADE ON UPDATE RESTRICT
);
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