如何在网站做电子杂志怎么查工程项目信息

以下是一个MySQL脚本示例，用于根据时间自动创建和管理分区表：

-- 1. 首先创建一个按时间分区的表（如果尚未存在）
CREATE TABLE IF NOT EXISTS time_partitioned_data (id INT AUTO_INCREMENT,data_value VARCHAR(255),created_at DATETIME NOT NULL,PRIMARY KEY (id, created_at)
)
PARTITION BY RANGE (TO_DAYS(created_at)) (PARTITION p_min VALUES LESS THAN (TO_DAYS('2023-01-01'))
);-- 2. 创建存储过程来自动管理分区
DELIMITER //
CREATE PROCEDURE auto_manage_partitions(IN table_name VARCHAR(64), IN days_ahead INT)
BEGINDECLARE done INT DEFAULT FALSE;DECLARE partition_name VARCHAR(64);DECLARE partition_value VARCHAR(64);DECLARE max_value DATE;DECLARE new_partition_date DATE;DECLARE new_partition_name VARCHAR(64);DECLARE new_partition_value INT;DECLARE alter_sql TEXT;-- 获取当前最大分区值SELECT MAX(TO_DAYS(created_at)) INTO @max_day FROM time_partitioned_data;SET max_value = IFNULL(FROM_DAYS(@max_day), CURDATE());-- 创建未来分区SET new_partition_date = max_value;WHILE DATEDIFF(DATE_ADD(new_partition_date, INTERVAL 1 MONTH), max_value) <= days_ahead DOSET new_partition_date = DATE_ADD(new_partition_date, INTERVAL 1 MONTH);SET new_partition_name = CONCAT('p_', DATE_FORMAT(new_partition_date, '%Y%m'));SET new_partition_value = TO_DAYS(new_partition_date);-- 检查分区是否已存在SELECT COUNT(*) INTO @partition_exists FROM information_schema.PARTITIONS WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'time_partitioned_data' AND PARTITION_NAME = new_partition_name;IF @partition_exists = 0 THENSET alter_sql = CONCAT('ALTER TABLE ', table_name, ' ADD PARTITION (PARTITION ', new_partition_name, ' VALUES LESS THAN (', new_partition_value, '))');PREPARE stmt FROM alter_sql;EXECUTE stmt;DEALLOCATE PREPARE stmt;SELECT CONCAT('Created partition: ', new_partition_name, ' for date: ', new_partition_date) AS message;END IF;END WHILE;-- 可选：删除旧分区（例如保留最近12个月的数据）/*SELECT PARTITION_NAME, PARTITION_DESCRIPTION INTO @old_partition, @old_valueFROM information_schema.PARTITIONSWHERE TABLE_SCHEMA = DATABASE()AND TABLE_NAME = 'time_partitioned_data'AND PARTITION_NAME != 'p_min'ORDER BY PARTITION_DESCRIPTION ASCLIMIT 1;IF TO_DAYS(CURDATE()) - @old_value > 365 THENSET @drop_sql = CONCAT('ALTER TABLE ', table_name, ' DROP PARTITION ', @old_partition);PREPARE stmt FROM @drop_sql;EXECUTE stmt;DEALLOCATE PREPARE stmt;SELECT CONCAT('Dropped old partition: ', @old_partition) AS message;END IF;*/
END //
DELIMITER ;-- 3. 创建事件定期执行分区管理
CREATE EVENT IF NOT EXISTS manage_partitions_event
ON SCHEDULE EVERY 1 MONTH
STARTS CURRENT_TIMESTAMP
DO
CALL auto_manage_partitions('time_partitioned_data', 90); -- 提前创建未来90天的分区-- 启用事件调度器
SET GLOBAL event_scheduler = ON;