我添加了一张我认为需要的表格,但现在不再使用它了。我应该如何删除该表?
我已经运行迁移,所以表在我的数据库。我的rails generate migration应该能够处理这个,但是我还没有弄清楚。
我试过了
rails generate migration drop_tablename
但是只是产生了一个空的迁移。
在Rails中放置表的“官方”方式是什么?
它们的区别,我看到的有如下几点:
1.curl是libcurl这个库支持的,wget是一个纯粹的命令行命令。
2.curl支持更多的协议。curl supports FTP, FTPS, HTTP, HTTPS, SCP, SFTP, TFTP, TELNET, DICT, LDAP, LDAPS, FILE, POP3, IMAP, SMTP and RTSP at the time of this writing. Wget supports HTTP, HTTPS and FTP.
3.curl 默认支持HTTP1.1(也支持1.0),而wget仅仅支持HTTP1.0规范。引用wget的man page中的一段话吧,Please be aware that Wget needs to know the size of the POST data in advance. It's not quite clear how to work around this limitation inherent in HTTP/1.0. Although HTTP/1.1 introduces chunked transfer that doesn't require knowing the request length in advance, a client can't use chunked unless it knows it's talking to an HTTP/1.1 server. And it can't know that until it receives a response, which in turn requires the request to have been completed -- a chicken-and-egg problem.
4.curl在指定要下载的链接时能够支持URL的序列或集合,而wget则不能这样;
5.wget支持递归下载,而curl则没有这个功能。(这是wget的一个主要好处,wget也是有优势的,呵呵)