July 2017
Intermediate to advanced
398 pages
11h 54m
Chinese
Content preview from Python数据处理
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114
｜
第
6
章
绍。如果你已经熟练掌握数据库的使用，可以大致浏览一下本节，继续阅读关于其他存储
方案以及何时使用数据库的内容。
你用
Siri
查过手机里的电话号码么？你用过谷歌搜索么？你有没有点击过
Twitter
或
Instagram
里的标签？这些操作都涉及对数据库（或一系列数据库，或数据库缓存）的简单
查询和响应。你有一个问题［在
YouTube
上新出了哪些关于猫（
Maru
）的有趣视频？］，
你向一个特定的数据库（
YouTube
搜索）提问，得到有趣的响应——可以观赏的搜索结果
列表。
在接下来的几节里，我们将简要讲述两种主要的数据库类型，强调了各自的利弊，并对比
了二者的优点和缺点。对于数据处理来说，你绝对
不
需要使用数据库，然而，随着数据处
理和分析变得更加复杂，数据库知识及其使用将变得更加重要，可以提高你存储和分析数
据的能力。
如果你对数据库感兴趣，我们会讲到用
Python
处理数据库的几个技巧，但显然我们没有足
够的时间全面讲述这个话题。我们强烈推荐你根据自己的兴趣去搜索更多的资料、视频和
教程。
6.7.1
关系型数据库
：
MySQL
和
PostgreSQL
对于来源很多、同时还有各种层次关联性的数据，关系型数据库是很好用的。关系型数
据库正如其名：如果你的数据连接类似于家谱，那么关系型数据库可能会适合你，比如
MySQL
。
关系型数据库通常使用一系列唯一标识符来匹配数据集。在
SQL
里我们一般把这些标识符
叫作
ID
。这些
ID
可以被其他数据集所用，用来查询和匹配数据连接。在这些连接好的数
据库中，我们可以进行
join ...
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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.