Example Explanation of Mysql Dynamic Update Database Script
- 2021-11-10 11:10:26
- OfStack
Specific
upgrade
The script is as follows:
Dynamic index deletion
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;
Add fields dynamically
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;
Other syntax is similar, mainly distinguishing
EXISTS
And
NOT EXISTS
The usage of.
Summarize