March 2021
Intermediate to advanced
265 pages
6h 50m
Chinese
Content preview from Presto实战
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.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.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.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.
104
｜
第
7
章
在
Cassandra
中处理数据的典型方法是使用为
Cassandra
设计的自定义查询语言：
Cassandra
查询语句
（
Cassandra
QueryLanguage
，
CQL
）。虽然
CQL
从表面上看很像
SQL
，
但它实际上缺少
SQL
的许多有用功能
，如
Join
。总的来说，它和
SQL
相当不同，无法直接
使用依赖
SQL
的标准工具。
然而，借助
Cassandra
连接器
，你可以对
Cassandra
中的数据进行
SQL
查询。最小配置就
是一个简单的
catalog
文件
，比如
etc/catalog/sitedata.properties
。这里的
Cassandra
集群记录
了一个网站上所有的用户交互，例如：
connector.name=cassandra
cassandra.contact-points=sitedata.example.com
有了这个简单的配置，用户就可以查询
Cassandra
中的数据。
Cassandra
中的任何键空间
（例如
cart
）都会在
Presto
中作为一个
schema
暴露出来，现在可以用普通的
SQL
查询表
了，比如
users
：
SELECT * FROM sitedata.cart.users;
该连接器支持许多配置属性，可以让你配置调整
Cassandra
集群的
catalog
，以及启用认证
和连接的
TLS
等。
7.4
流式系统连接器示例
：
Kafka
流式系统和发布
–
订阅（
pub/sub
）系统旨在处理实时数据源。例如，
LinkedIn
创造的
Apache Kafka
便
是一个高吞吐量、低时延的平台 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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.