Mysql動態更新資料庫指令碼的示例講解
阿新 • • 發佈:2020-01-09
具體的upgrade
指令碼如下:
動態刪除索引
DROP PROCEDURE IF EXISTS UPGRADE; DELIMITER $$ CREATE PROCEDURE UPGRADE() BEGIN -- RESOURCE.AUDIO_ATTRIBUTE IF EXISTS(SELECT * FROM INFORMATION_SCHEMA.STATISTICS WHERE TABLE_SCHEMA = 'RESOURCE' AND TABLE_NAME = 'AUDIO_ATTRIBUTE' AND INDEX_NAME = 'resource_publish_resource_id_index') THEN ALTER TABLE `AUDIO_ATTRIBUTE` DROP INDEX resource_publish_resource_id_index; END IF; END$$ DELIMITER ; CALL UPGRADE(); DROP PROCEDURE IF EXISTS UPGRADE;
動態新增欄位
DROP PROCEDURE IF EXISTS UPGRADE; DELIMITER $$ CREATE PROCEDURE UPGRADE() BEGIN -- HOMEWORK.HOMEWORK_QUESTION_GROUP.FROM_ID IF NOT EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = 'HOMEWORK' AND TABLE_NAME = 'HOMEWORK_QUESTION_GROUP' AND COLUMN_NAME = 'FROM_ID') THEN ALTER TABLE `HOMEWORK_QUESTION_GROUP` ADD COLUMN FROM_ID VARCHAR(50) NULL; END IF; -- HOMEWORK.HOMEWORK_QUESTION_GROUP.QUESTION_TYPE IF NOT EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = 'HOMEWORK' AND TABLE_NAME = 'HOMEWORK_QUESTION_GROUP' AND COLUMN_NAME = 'QUESTION_TYPE') THEN ALTER TABLE `HOMEWORK_QUESTION_GROUP` ADD COLUMN QUESTION_TYPE VARCHAR(50) NULL; END IF; -- HOMEWORK.HOMEWORK_QUESTION_GROUP.DIFFICULTY IF NOT EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = 'HOMEWORK' AND TABLE_NAME = 'HOMEWORK_QUESTION_GROUP' AND COLUMN_NAME = 'DIFFICULTY') THEN ALTER TABLE `HOMEWORK_QUESTION_GROUP` ADD COLUMN DIFFICULTY VARCHAR(50) NULL; END IF; END$$ DELIMITER ; CALL UPGRADE(); DROP PROCEDURE IF EXISTS UPGRADE;
其他語法類似,主要區分EXISTS
和NOT EXISTS
的用法。
總結
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