Do the crawler climb took some questions and answers in the mongo database data storage, and my single dictionary design is: {" k1 ": the title of" q&a ", "url" : "document links", "k2" : "the q&a time", "k3" : "to answer a few," {" zhang ", "his answer is... ", "bill" : "his answer is... ", "detective" : "his answer is... "}}, my data structure is that the only won't change is that k1 and url, is the question and answer the questions and answers document link address will not change, the remaining anyone at any time to review, so this dictionary will be regularly updated, such specific what to do, how data storage operation, how to operate the query