Remove the condition of "unique not null" from orderid, which is irrelevant
when we only collect data and don't trade.
Remove the constraint of "not null unique" on orderid, which is irrelevant
when we don't trade but only collect data.
Instead of always accepting the first transaction record, we discard it
if its volume is 0.
1. Redirect the output of watcher.sh to watcher.log
2. Correct the work directory.