when should I use a relational database and when should I use a non-relational database? ...
I am a rookie. I set up a website because I had to record a table of mysql caused by each visit of user agent,. 100000 rows of data were recorded in a year, which became the size of 50Mb. However, from a sensory point of view, it does not seem to affect...
A login request, the username parameter and password parameter have been set two parameters of username and password are not seen in the chrome browser to submit, what is the reason? ...
6.5 comment a b (). Next () is followed by a 6.5. Why does the second next () cause console.log (6.5) to be executed again? How to understand this problem? ...
using the send mail function encapsulated by class.phpmailer.php to send mail, it is found that it may not be sent once or twice a week. I think it may be the reason for the server, but I don t know how to check it, and I don t have the account of the...
< H1 > hadoop startup error < H1 > configuration files are all written and then started [root@master logs]-sharp start-dfs.sh Starting namenodes on [master] Last login: Wed Jul 4 16:30:19 CST 2018 on pts 0 bash v3.2+ is required. Sorry. Starting da...