November 2021
Intermediate to advanced
410 pages
12h 1m
Chinese
Content preview from MongoDB权威指南（第3版）
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入门指南
｜
23
如果希望始终使用自定义提示（或者配置几个可以在
shell
中进行切换的自定义提示），那
么
.mongorc.js
文件是进行此设置的好地方。
2.7.5
编辑复杂变量
shell
的多行支持比较有限：不能编辑前面的行。如果编辑到第
15
行时发现第
1
行有一个
错误，那会非常让人懊恼。因此，对于较大的代码块或者对象，可能需要在编辑器中编辑
它们。为此，可以在
shell
中设置
EDITOR
变量（也可以在环境变量中进行设置）：
> EDITOR="/usr/bin/emacs"
现在，如果要编辑一个变量，可以使用
edit varname
命令，如下所示：
> var wap = db.books.findOne({title: "War and Peace"});
> edit wap
完成更改后，保存并退出编辑器。变量将被重新解析并加载回
shell
。
将
EDITOR="/
path
/
to
/
editor
";
添加到
.mongorc.js
文件中，以后就不用再设置此变量了。
2.7.6
不便使用的集合名称
大多数情况下可以使用
db.
collectionName
语法来获得一个集合的内容，但如果集合名称
是保留字或是无效的
JavaScript
属性名称，那么此方法就不能正常工作了。
假设我们正在尝试访问
version
集合
。我们不能使用
db.version
，因为
db.version
是
db
上
的一个方法（它会返回正在运行的
MongoDB
服务器版本）
：
> db.version
function () {
return this.serverBuildInfo().version; ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.