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lines changed Original file line number Diff line number Diff line change @@ -722,7 +722,7 @@ SELECT NO FROM course WHERE t_no = ( SELECT NO FROM teacher WHERE NAME = '张旭
722722
723723``` mysql
724724SELECT * FROM score WHERE c_no = (
725- SELECT no FROM course WHERE t_no = (
725+ SELECT no FROM course WHERE t_no = (
726726 SELECT no FROM teacher WHERE NAME = ' 张旭'
727727 )
728728);
@@ -1570,7 +1570,7 @@ SELECT * FROM user;
15701570>
15711571> ` @@AUTOCOMMIT = 0 ` 时,使用 ` COMMIT ` 命令提交事务。
15721572>
1573- > 3 . ** 事务回滚**
1573+ > 3 . ** 事务回滚**
15741574>
15751575> ` @@AUTOCOMMIT = 0 ` 时,使用 ` ROLLBACK ` 命令回滚事务。
15761576
@@ -1675,17 +1675,17 @@ ROLLBACK;
16751675
16761676### 事务的隔离性
16771677
1678- ** 事务的隔离性可分为四种 ( 性能从低到高 ) : **
1678+ ** 事务的隔离性可分为四种 ( 性能从低到高 )** :
16791679
1680- 1 . ** READ UNCOMMITTED ( 读取未提交 ) **
1680+ 1 . ** READ UNCOMMITTED ( 读取未提交 )**
16811681
16821682 如果有多个事务,那么任意事务都可以看见其他事务的** 未提交数据** 。
16831683
1684- 2 . ** READ COMMITTED ( 读取已提交 ) **
1684+ 2 . ** READ COMMITTED ( 读取已提交 )**
16851685
16861686 只能读取到其他事务** 已经提交的数据** 。
16871687
1688- 3 . ** REPEATABLE READ ( 可被重复读 ) **
1688+ 3 . ** REPEATABLE READ ( 可被重复读 )**
16891689
16901690 如果有多个连接都开启了事务,那么事务之间不能共享数据记录,否则只能共享已提交的记录。
16911691
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