我对我的这些答案有一些疑问,如果你们能澄清我是对还是错,我将不胜感激,一个员工可以被分配到多个项目,一个项目可以有多个员工。考虑以下关系模式,并为以下查询编写SQL语句。(5分)(a) SELECT empName FROM Employees WHERE empDOB < '31-01-1980' AND projType = (SELECT projTypeempID FROM Employees GROUP BY (SELECT projID From Projects) HAVING COUNT(*)&g
我希望有更多知识的人能在Ubuntu16.04及以后的版本中解释一些关于做apt-get upgrade的事情。我看到的行为是,apt-get upgrade有时不会安装新的内核包,有时会:The following packages have been kept back:我知道做dist-upgrade会安装这些软件包(所以不要重复这个<e
我现在已经安装了PHP5.6 PHP 5.6.17-1+deb.sury.org~trusty+2 (cli),安装在薄荷17.2 x64 (肉桂)上。如果我试图安装mit-scheme,我会得到:Reading state information... Done The following packages were automatically installed and are no longer required: