Just because these rules are part of the logical data model, one should not assume that they must be enforced by a database.
由于这些规则是逻辑数据模型的一部分，所以不应该认为一个数据库必须实施这些规则。
"Technology is easy to develop," he says. "Developing a new attitude, moving the culture from one mental model to another, that's the difficult part."
“科技是容易开发，”他说，“开发需要一个新的态度，从一个文化思维模式转换到另一个，那是困难的方面。”
One of the handiest things about environment variables is that they are a standard part of the UNIX process model.
环境变量的最便利之处在于：它们是UNIX进程模型的标准部分。
应用推荐