SELECTTABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME,REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAMEFROMINFORMATION_SCHEMA.KEY_COLUMN_USAGEWHERETABLE_SCHEMA = ’mydbname’AND REFERENCED_TABLE_NAME = ’表名’;導(dǎo)出所有外鍵語句

SELECTCONCAT(’ALTER TABLE ’, TABLE_NAME, ’ ADD CONSTRAINT ’, CONSTRAINT_NAME, ’ FOREIGN KEY (’, COLUMN_NAME, ’) REFERENCES ’, REFERENCED_TABLE_NAME, ’(’, REFERENCED_COLUMN_NAME, ’) ON DELETE CASCADE ON UPDATE CASCADE;’)FROMINFORMATION_SCHEMA.KEY_COLUMN_USAGEWHERETABLE_SCHEMA = ’mydbname’AND REFERENCED_TABLE_NAME IS NOT NULL;刪除所有外鍵語句

SELECTCONCAT(’ALTER TABLE ’, TABLE_NAME, ’ DROP FOREIGN KEY ’, CONSTRAINT_NAME, ’;’)FROMINFORMATION_SCHEMA.KEY_COLUMN_USAGEWHERETABLE_SCHEMA = ’mydbname’AND REFERENCED_TABLE_NAME IS NOT NULL;自增導(dǎo)出創(chuàng)建自增字段的語句

SELECTCONCAT( ’ALTER TABLE `’, TABLE_NAME, ’` ’, ’MODIFY COLUMN `’, COLUMN_NAME, ’` ’, UPPER( COLUMN_TYPE ), ’ NOT NULL AUTO_INCREMENT COMMENT '’,COLUMN_COMMENT,’';’ ) as ’ADD_AUTO_INCREMENT’FROMinformation_schema.COLUMNS WHERETABLE_SCHEMA = ’mydbname’ AND EXTRA = UPPER( ’AUTO_INCREMENT’ ) ORDER BYTABLE_NAME ASC;創(chuàng)建刪除所有自增字段

SELECTCONCAT( ’ALTER TABLE `’, TABLE_NAME, ’` ’, ’MODIFY COLUMN `’, COLUMN_NAME, ’` ’, UPPER( COLUMN_TYPE ), ’ NOT NULL;’ ) as ’DELETE_AUTO_INCREMENT’FROMinformation_schema.COLUMNS WHERETABLE_SCHEMA = ’mydbname’ AND EXTRA = UPPER( ’AUTO_INCREMENT’ ) ORDER BYTABLE_NAME ASC;索引導(dǎo)出所有索引

SELECTCONCAT(’ALTER TABLE `’,TABLE_NAME,’` ’,’ADD ’,IF(NON_UNIQUE = 1,CASEUPPER( INDEX_TYPE ) WHEN ’FULLTEXT’ THEN’FULLTEXT INDEX’ WHEN ’SPATIAL’ THEN’SPATIAL INDEX’ ELSE CONCAT( ’INDEX `’, INDEX_NAME, ’` USING ’, INDEX_TYPE ) END,IF(UPPER( INDEX_NAME ) = ’PRIMARY’,CONCAT( ’PRIMARY KEY USING ’, INDEX_TYPE ),CONCAT( ’UNIQUE INDEX `’, INDEX_NAME, ’` USING ’, INDEX_TYPE ))),CONCAT( ’(`’, COLUMN_NAME, ’`)’ ),’;’ ) AS ’ADD_ALL_INDEX’ FROMinformation_schema.STATISTICS WHERETABLE_SCHEMA = ’mydbname’ ORDER BYTABLE_NAME ASC,INDEX_NAME ASC;刪除所有索引

SELECTCONCAT( ’ALTER TABLE `’, TABLE_NAME, ’` ’, CONCAT( ’DROP ’, IF ( UPPER( INDEX_NAME ) = ’PRIMARY’, ’PRIMARY KEY’, CONCAT( ’INDEX `’, INDEX_NAME, ’`’ ))), ’;’ ) AS ’DELETE_ALL_INDEX’ FROMinformation_schema.STATISTICS WHERETABLE_SCHEMA = ’mydbname’ ORDER BYTABLE_NAME ASC;數(shù)據(jù)合并

在數(shù)據(jù)遷移合并的時候，比較棘手的是不同數(shù)據(jù)庫主鍵重復(fù)，那么我們就要批量修改主鍵的值，為了避免重復(fù)我們可以把自增的數(shù)字改為字符串

步驟基本上有以下幾步

修改主鍵值的時候要注意

如果包含id和pid這種自關(guān)聯(lián)的情況下是不能直接修改值的，就需要先刪除約束再添加。

比如

刪除自約束

ALTER TABLE `t_director` DROP FOREIGN KEY `fk_directorpid`;

修改值

update t_director set directorid=directorid+100000000;update t_director set directorid=CONV(directorid,10,36);update t_director set directorpid=directorpid+100000000 WHERE directorpid is not null;update t_director set directorpid=CONV(directorpid,10,36) WHERE directorpid is not null;

添加自約束

ALTER TABLE t_director ADD CONSTRAINT fk_directorpid FOREIGN KEY (directorpid) REFERENCES t_director(directorid) ON DELETE CASCADE ON UPDATE CASCADE;

注意

CONV(directorpid,10,36)后兩個參數(shù)為原數(shù)字進(jìn)制和要轉(zhuǎn)換后的進(jìn)制。

第一個參數(shù)只要內(nèi)容是數(shù)字就算類型為varchar也可以轉(zhuǎn)換。

以上就是Mysql中索引和約束的示例語句的詳細(xì)內(nèi)容，更多關(guān)于MySQL 索引和約束的資料請關(guān)注好吧啦網(wǎng)其它相關(guān)文章！