数据库：
1）In a MS SQL statement what can you do to limit the amount of records that
are locked during a SELECT query?
VB：
2）In MS VB how do you make sure all variables are defined?
最后这个不懂目的在哪里：
3）In an embedded device you need to read the value of a user input switch
what do you need to do to make this robust?
谢大家解惑~~~
