Level

Level in computer science

下面总结了一些computer science 中的level。

Levels of exception safety

exception safety的等级：

• No-throw guarantee
• Strong exception safety
• Basic exception safety
• No exception safety

Levels of database normalization

• UNF (1970)
• 1NF (1970)
• 2NF (1971)
• 3NF (1971)
• EKNF (1982)
• BCNF (1974)
• 4NF (1977)
• ETNF (2012)
• 5NF (1979)
• DKNF (1981)
• 6NF (2003) |

Level of Consistency model

• Strict consistency
• Sequential consistency
• Causal consistency
• ......

Level of database transaction isolation

参见 数据库事务的四大特性以及事务的隔离级别。

Tradeoff

1、在现实中，我们往往需要在诸多因素中进行tradeoff，可能因为其它目的而放弃更高level，而选择较低level，典型的例子有:

a、performance and exception safety tradeoff，参见工程programming-language的Exception\Exception-Safety\Level-of-exception-safety章节