| 1. | Read uncommitted ? permits dirty reads but not lost updates
未授权读取允许脏读取，但不允许更新丢失。 |
| 2. | Second lost updates problem ? a special case of an unrepeatable read
两次更新问题无法重复读取的特例。 |
| 3. | Lost update : one thread reads a record , a second thread updates the record , and then the first thread overwrites the second thread ' s update
线程1读了一条记录，线程2更新了一条记录，接着线程1覆盖了线程2的更新。 |
| 4. | A lower isolation level increases the ability of many users to access data at the same time , but increases the number of concurrency effects such as dirty reads or lost updates users might encounter
较低的隔离级别可以增强许多用户同时访问数据的能力，但也增加了用户可能遇到的并发副作用（例如脏读或丢失更新）的数量。 |
| 5. | A lower isolation level increases the ability of many users to access data at the same time , but increases the number of concurrency effects , such as dirty reads or lost updates , that users might encounter
较低的隔离级别会提高多名用户同时访问数据的能力，但是也会增加用户可能遭遇的并发影响（如脏读或更新丢失）的次数。 |
| 6. | If the two transactions update rows using a single update statement and do not base the update on the previously retrieved values , lost updates cannot occur at the default isolation level of read committed
如果两个事务使用单个update语句更新行，并且没有按照以前的检索值进行更新，则在设置为提交读的默认隔离级别时，不会发生更新丢失。 |
| 7. | This isolation level eliminates the possibility that one transaction could overwrite changes made by another concurrent transaction ( the second lost updates problem ) if all data access is performed in a single atomic database transaction
如果所有的数据访问都是在统一的原子数据库事务中，此隔离级别将消除一个事务在另外一个并发事务过程中覆盖数据的可能性（第二个事务更新丢失问题） 。 |
| 8. | Transactions must be run at an isolation level of at least repeatable read to prevent lost updates that can occur when two transactions each retrieve the same row , and then later update the row based on the originally retrieved values
当两个事务中的每个事务都要检索相同的行，然后又根据最初的检索值更新行时，可能发生更新丢失。此时，事务必须至少以的可重复读的隔离级别运行，以防止更新丢失。 |
