MySQL分層數據幫助 - 閉包表方法

Question

我正在嘗試在MySQL中實現一個系統來存儲分層數據。 我決定去與實現的系統在這里如由比爾Karwin開始在幻燈片編號40.我試圖建立數據庫，以便在EntryPaths表自動維護。

更新：我已經更新了數據庫創建SQL了一下。 我想，我有1/2工作的東西需要更新。 運行數據庫后創建SQL，請嘗試以下操作

首先看看這個條目是怎么看的

-- Example query to return a full library entry (0x02 is the entry iD)
SELECT `Library`.* FROM `Library`
LEFT JOIN `EntryPaths` ON `Library`.`iD` = `EntryPaths`.`descendant`
WHERE `EntryPaths`.`ancestor` = 0x02
ORDER BY `Library`.`subsectionOf`, `Library`.`subsectionOrder`

這個看起來如何

-- Example query to return a full library entry (0x08 is the entry iD)
SELECT `Library`.* FROM `Library`
LEFT JOIN `EntryPaths` ON `Library`.`iD` = `EntryPaths`.`descendant`
WHERE `EntryPaths`.`ancestor` = 0x08
ORDER BY `Library`.`subsectionOf`, `Library`.`subsectionOrder`

觀看的第一個條目有幾個孩子，第二個沒有孩子。 運行以下更新以將“College Years”節點（及其子節點）重新顯示給John Doe

UPDATE  `Library` SET  `subsectionOf` =  0x08 WHERE  `Library`.`iD` = 0x04;

如果您重新運行上述兩個select語句，您將看到項目已從Jane Doe刪除，但它們尚未按預期添加到John Doe 。 Library_Update觸發器有問題，但我已經沒有想法嘗試修復它了。

數據庫使用示例數據創建SQL：

-- MYSQL
SET FOREIGN_KEY_CHECKS=0;
DROP TRIGGER IF EXISTS Library_Insert;
DROP TRIGGER IF EXISTS Library_Update;
DROP TABLE IF EXISTS Users;
DROP TABLE IF EXISTS Attributes;
DROP TABLE IF EXISTS LibraryHistory;
DROP TABLE IF EXISTS EntryPaths;
DROP TABLE IF EXISTS Library;
SET FOREIGN_KEY_CHECKS=1;


CREATE TABLE `Users` (
    `iD`              VARBINARY(16) NOT NULL,   -- UUID & PK
    `libraryID`       VARBINARY(16),            -- Library UUID & FK (The library entry for this person)
    `email`           NVARCHAR(255) NOT NULL,   -- Email address
    `nickname`        NVARCHAR(255) NOT NULL,   -- Nickname used for display
    `firstname`       NVARCHAR(255),            -- Real first name
    `lastname`        NVARCHAR(255),            -- Real last name
    `joinDate`        DATETIME NOT NULL,        -- Date the account was created
    PRIMARY KEY (`iD`)
) ENGINE = MYISAM;


CREATE TABLE `Library` (
    `iD`              VARBINARY(16) NOT NULL,   -- UUID & PK
    `name`            NVARCHAR(500) NOT NULL,   -- Name for the entry
    `contentType`     NVARCHAR(50)  NOT NULL,   -- Mime type of data
    `content`         LONGBLOB      NOT NULL,   -- Data a for the entry
    `subsectionOf`    VARBINARY(16),            -- Library UUID & FK
    `subsectionOrder` INT,                      -- Oder of Subsections 
    `lastModifiedBy`  VARBINARY(16),            -- User UUID & FK
    `lastModified`    DATETIME      NOT NULL,   -- Last time the record was updated
    PRIMARY KEY (`iD`),
    FOREIGN KEY (`subsectionOf`) REFERENCES Library(`iD`) ON DELETE CASCADE,
    FOREIGN KEY (`lastModifiedBy`) REFERENCES Users(`iD`),
    INDEX(`name`)
) ENGINE = MYISAM;

-- Trigger to update the EntryPaths table for new entries
DELIMITER //
CREATE TRIGGER `Library_Insert` AFTER INSERT ON `Library` FOR EACH ROW 
BEGIN
    INSERT INTO `EntryPaths` (`ancestor`, `descendant`, `len`)
        SELECT `ancestor`, NEW.`iD`, len + 1 FROM `EntryPaths`
            WHERE `descendant` = NEW.`subsectionOf`
            UNION ALL SELECT NEW.`iD`, NEW.`iD`, 0;
END; //
DELIMITER ;


DELIMITER //
CREATE TRIGGER `Library_Update` BEFORE UPDATE ON `Library` FOR EACH ROW 
BEGIN
    -- Add the old entry into the history table
    INSERT INTO `LibraryHistory` VALUES(UNHEX(REPLACE(UUID(),'-','')),
        OLD.`iD`, OLD.`name`, OLD.`contentType`, OLD.`content`,
        OLD.`subsectionOf`, OLD.`subsectionOrder`, OLD.`lastModifiedBy`,
        OLD.`lastModified`);

    -- From http://www.mysqlperformanceblog.com/2011/02/14/moving-subtrees-in-closure-table/
    IF OLD.`subsectionOf` != NEW.`subsectionOf` THEN
        -- Remove the node from its current parent
        DELETE a FROM `EntryPaths` AS a
        JOIN `EntryPaths` AS d ON a.`descendant` = d.`descendant`
        LEFT JOIN `EntryPaths` AS x
        ON x.`ancestor` = d.`ancestor` AND x.`descendant` = a.`ancestor`
        WHERE d.`ancestor` = OLD.`iD` AND x.`ancestor` IS NULL;

        -- Add the node to its new parent
        -- FIXME: Not Working yet
        INSERT `EntryPaths` (`ancestor`, `descendant`, `len`)
        SELECT supertree.`ancestor`, subtree.`descendant`, supertree.`len`+subtree.`len`+1
        FROM `EntryPaths` AS supertree JOIN `EntryPaths` AS subtree
        WHERE subtree.`ancestor` = NEW.`iD`
        AND supertree.`descendant` = NEW.`subsectionOf`;
    END IF;
END; //
DELIMITER ;


CREATE TABLE `EntryPaths` (
    `ancestor`      VARBINARY(16) NOT NULL,
    `descendant`    VARBINARY(16) NOT NULL,
    `len`           VARBINARY(16) NOT NULL,
    PRIMARY KEY (`ancestor`, `descendant`),
    FOREIGN KEY (`ancestor`) REFERENCES Library(`iD`) ON DELETE CASCADE,
    FOREIGN KEY (`descendant`) REFERENCES Library(`iD`) ON DELETE CASCADE
) ENGINE = MYISAM;


CREATE TABLE `LibraryHistory` (
    `iD`              VARBINARY(16) NOT NULL,   -- UUID & PK
    `libraryID`       VARBINARY(16) NOT NULL,   -- Library UUID & FK
    `name`            NVARCHAR(500) NOT NULL,   -- Name for the entry
    `contentType`     NVARCHAR(50)  NOT NULL,   -- Mime type of data
    `content`         LONGBLOB      NOT NULL,   -- Data a for the entry
    `subsectionOf`    VARBINARY(16),            -- Library UUID & FK
    `subsectionOrder` INT,                      -- Oder of Subsections 
    `lastModifiedBy`  VARBINARY(16),            -- User UUID & FK
    `lastModified`    DATETIME      NOT NULL,   -- Last time the record was updated
    PRIMARY KEY (`iD`),
    FOREIGN KEY (`libraryID`) REFERENCES Library(`iD`) ON DELETE CASCADE,
    FOREIGN KEY (`lastModifiedBy`) REFERENCES Users(`iD`)
) ENGINE = MYISAM;


CREATE TABLE `Attributes` (
    `iD`              VARBINARY(16) NOT NULL,  -- UUID & PK  (Potentially could be removed)
    `libraryID`       VARBINARY(16) NOT NULL,  -- Library UUID & FK
    `name`            NVARCHAR(500) NOT NULL,  -- Name of attribute
    `dataType`        INT           NOT NULL,  -- The type of data the attribute holds (int, date, string, etc.)
    `data`            NVARCHAR(500) NOT NULL,  -- Value of attribute
    `lastModifiedBy`  VARBINARY(16),           -- User UUID & FK
    `lastModified`    DATETIME      NOT NULL,  -- Last time the record was updated
    PRIMARY KEY (`iD`),
    FOREIGN KEY (`libraryID`) REFERENCES Library(`iD`) ON DELETE CASCADE,
    INDEX (`name`)
) ENGINE = MYISAM;

ALTER TABLE `Users` ADD CONSTRAINT FK_User_Library FOREIGN KEY (`libraryID`) REFERENCES Library(`iD`);

-- Example Data
INSERT INTO `Library` VALUES(0x01, 'People', 'text/plain', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', NULL, NULL, NULL, '2011-11-16 20:27:54');
INSERT INTO `Library` VALUES(0x02, 'Jane Doe', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', NULL, NULL, NULL, '2011-11-16 20:29:13');
INSERT INTO `Library` VALUES(0x03, 'Younger Years', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', 0x02, 1, NULL, '2011-11-16 00:00:00');
INSERT INTO `Library` VALUES(0x04, 'College Years', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', 0x02, 2, NULL, '2011-11-16 20:31:52');
INSERT INTO `Library` VALUES(0x05, 'Yale', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', 0x04, 2, NULL, '2011-11-16 20:32:44');
INSERT INTO `Library` VALUES(0x06, 'Old Age', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar find me here scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', 0x02, 3, NULL, '2011-11-16 20:31:52');
INSERT INTO `Library` VALUES(0x07, 'Community College', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', 0x04, 1, NULL, '2011-11-16 20:33:11');
INSERT INTO `Library` VALUES(0x08, 'John Doe', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', NULL, NULL, NULL, '2011-11-16 20:34:40');
INSERT INTO `Library` VALUES(0x09, 'Planets', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', NULL, NULL, NULL, '2011-11-16 20:27:54');
INSERT INTO `Library` VALUES(0x10, 'Earth', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', NULL, NULL, NULL, '2011-11-16 20:27:54');
INSERT INTO `Library` VALUES(0x11, 'Mars', 'text/x-markup', 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam pulvinar scelerisque quam, vel convallis turpis porttitor in. Curabitur pulvinar fermentum pulvinar. Mauris lorem lacus, gravida porta lacinia vitae, dictum ac eros. Aliquam magna arcu, lacinia ac dictum sed, euismod eu elit. Sed semper nulla at velit pulvinar in vehicula risus tempus. Phasellus id nisl libero, id porttitor purus. Integer aliquet semper aliquam. Morbi elit mi, pellentesque et ornare nec, iaculis gravida elit. Sed in luctus lorem. Maecenas a purus at lectus condimentum congue.', NULL, NULL, NULL, '2011-11-16 20:27:54');
INSERT INTO `Attributes` VALUES(0x01, 0x02, 'TypeOf', 1, 0x01, NULL, '2011-11-16 20:34:40');
INSERT INTO `Attributes` VALUES(0x02, 0x02, 'BirthDate', 2, '19770521', NULL, '2011-11-16 20:34:40');
INSERT INTO `Attributes` VALUES(0x03, 0x02, 'EyeColor', 3, 'Brown', NULL, '2011-11-16 20:34:40');
INSERT INTO `Attributes` VALUES(0x04, 0x08, 'TypeOf', 1, 0x01, NULL, '2011-11-16 20:34:40');
INSERT INTO `Attributes` VALUES(0x05, 0x08, 'BirthDate', 2, '19740521', NULL, '2011-11-16 20:34:40');
INSERT INTO `Attributes` VALUES(0x06, 0x10, 'TypeOf', 1, 0x08, NULL, '2011-11-16 20:34:40');
INSERT INTO `Attributes` VALUES(0x07, 0x11, 'TypeOf', 1, 0x08, NULL, '2011-11-16 20:34:40');

Answer 1

在Libary_Update觸發器的INSERT語句中，您有以下行：

WHERE subtree.`ancestor` = NEW.`iD`

但是你沒有更新ID字段，所以我認為你沒有NEW.iD值。 該行是否應該使用OLD.iD？