DISCARD
Discard all commands issued after MULTI
More: http://redis.io/commands/discard, http://www.redis.cn/commands/discard.html
EXEC
Execute all commands issued after MULTI
More: http://redis.io/commands/exec, http://www.redis.cn/commands/exec.html
MULTI
Mark the start of a transaction block
More: http://redis.io/commands/multi, http://www.redis.cn/commands/multi.html
UNWATCH
Forget about all watched keys
More: http://redis.io/commands/unwatch, http://www.redis.cn/commands/unwatch.html
WATCH key [key ...]
Watch the given keys to determine execution of the MULTI/EXEC block
More: http://redis.io/commands/watch, http://www.redis.cn/commands/watch.html
Redis(2.8.3) 命令学习 - Transactions
原文：http://www.cnblogs.com/huey/p/4351064.html