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首先看一个存储过程，这个存储过程是为了构造数据使用的。当然贴出来的存储过程简化了一些不必要的表结构。
CREATE PROCEDURE modifyRootEntry()BEGIN DECLARE done INT DEFAULT FALSE; DECLARE userId INT; DECLARE userIdIter CURSOR FOR SELECT DISTINCT user_id from entries; OPEN userIdIter; read_loop: LOOP FETCH userIdIter INTO userId; IF done THEN LEAVE read_loop; END IF; INSERT INTO entries (id, name, user_id, parent_id) VALUES(0, 'root_parent', userId, 0); UPDATE entries SET parent_id=0 where user_id=userId AND name='file_root' AND parent_id is NULL; END LOOP; CLOSE userIdIter;END;
CREATE PROCEDURE modifyRootEntry()BEGIN DECLARE done INT DEFAULT FALSE; DECLARE userId INT; DECLARE userIdIter CURSOR FOR SELECT DISTINCT user_id from entries; START TRANSACTION; // here ! OPEN userIdIter; read_loop: LOOP FETCH userIdIter INTO userId; IF done THEN LEAVE read_loop; END IF; INSERT INTO entries (id, name, user_id, parent_id) VALUES(0, 'root_parent', userId, 0); UPDATE entries SET parent_id=0 where user_id=userId AND name='file_root' AND parent_id is NULL; END LOOP; CLOSE userIdIter; COMMIT;// here !END;
UPDATE entries SET parent_id=0 where user_id=userId AND name='file_root' AND parent_id is NULL;
CREATE PROCEDURE modifyRootEntry()BEGIN DECLARE done INT DEFAULT FALSE; DECLARE userId INT; DECLARE userIdIter CURSOR FOR SELECT DISTINCT user_id from entries; START TRANSACTION; // here ! OPEN userIdIter; read_loop: LOOP FETCH userIdIter INTO userId; IF done THEN LEAVE read_loop; END IF; INSERT INTO entries (id, name, user_id, parent_id) VALUES(0, 'root_parent', userId, 0); END LOOP; UPDATE entries SET parent_id=0 where user_id=userId AND name='file_root' AND parent_id is NULL; // here! CLOSE userIdIter; COMMIT;// here !END;
CREATE PROCEDURE pFastCreateNums (cnt INT UNSIGNED)BEGINDECLARE s INT UNSIGNED DEFAULT 1;TRUNCATE TABLE Nums;INSERT INTO Nums SELECT s;WHILE s*2 <= cnt DOBEGININSERT INTO Nums SELECT a+s FROM Nums;SET s = s*2;END;END WHILE;END;
