Guida ai dati gerarchici di MySQL - Metodo tabella di chiusura

Question

Sto cercando di implementare un sistema in MySQL per archiviare i dati gerarchici. Ho deciso di andare con il sistema implementato here come descritto da Bill Karwin a partire dalla diapositiva numero 40. Sto provando a configurare il database in modo che la tabella EntryPaths venga mantenuta automaticamente.

Aggiornamento: Ho aggiornato il database per creare un po 'di SQL. Ho 1/2 cose funzionanti per un aggiornamento, penso. Dopo aver eseguito il database creare SQL provare la seguente

prima vedere come questa voce appare

-- 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` 

e come questo si guarda

-- 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` 

La prima voce di visto ha diversi figli, il secondo non ha bambini. Eseguire il seguente aggiornamento per Reparent nodo dei 'College Years' (e dei suoi figli) per John Doe

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

Se si ri-eseguire queste due istruzioni SELECT si vedrà che gli oggetti sono stati rimossi da Jane Doe ma hanno non è stato aggiunto a John Doe come previsto. Il trigger Library_Update è in errore ma non riesco a trovare le idee per provare a risolverlo.

Il database creare SQL con i dati di esempio:

-- 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

Nella vostra istruzione INSERT nel trigger Libary_Update si ha la seguente riga:

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

ma non si sta aggiornando il campo ID in modo Non penso che avrai un valore NEW.iD. La linea dovrebbe forse usare OLD.iD?