摘要：
Summary MacOS Sierra To install the newest Xcode Command Line Tools, you’ll need the latest version of macOS. If you’ve owned your Mac for several yea 阅读全文
摘要：
新增非空列： alter table t_test add column user_id integer; update t_test set user_id=0; alter table t_test alter column user_id SET NOT NULL; 阅读全文