And do not require any additional locking during traversal ,遍历期间也不要求额外的锁定。
This additional locking information must be maintained in the transaction log 事务日志必须维护此附加锁定信息。
Additional lock spring 附加锁杆簧
Cursors also support their own concurrency specifications , some of which generate additional locks on the rows in each fetch 游标也支持自己的并发规定,其中某些会在每次提取时生成额外的锁。