Keyspaces

A cluster is a container for keyspaces. A keyspace is the outermost container for data in Cassandra, corresponding closely to a schema in a relational database. The keyspace can include operational elements, such as replication factor and data center awareness. Let's create a keyspace:

-- create a keyspace 'my_keyspace'
create keyspace my_keyspace with replication={'class':'SimpleStrategy', 'replication_factor':1}; -- use the keyspace
use my_keyspace; -- drop the keyspace
drop keyspace my_keyspace;

Creating a table

To create a table type the following in cqlsh, note that you must first create a keyspace and then use that keyspace:

CREATE TABLE users (
firstname text,
lastname text,
age int,
email text,
city text,
PRIMARY KEY (lastname)
);

Describe a table

To see detail information about a table type:

DESCRIBE TABLE users;

Insert records

To insert records in the table type:

INSERT INTO users (firstname, lastname, age, email, city) VALUES ('John', 'Smith', 46, 'johnsmith@email.com', 'Sacramento');
INSERT INTO users (firstname, lastname, age, email, city) VALUES ('Jane', 'Doe', 36, 'janedoe@email.com', 'Beverly Hills');
INSERT INTO users (firstname, lastname, age, email, city) VALUES ('Rob', 'Byrne', 24, 'robbyrne@email.com', 'San Diego');

Querying a table

To query a table type the following:

SELECT * FROM users;

 lastname | age | city          | email               | firstname
----------+-----+---------------+---------------------+-----------
Doe | 36 | Beverly Hills | janedoe@email.com | Jane
Byrne | 24 | San Diego | robbyrne@email.com | Rob
Smith | 46 | Sacramento | johnsmith@email.com | John (3 rows)

We can filter the result by using a predicate:

SELECT * FROM users WHERE lastname= 'Doe';

 lastname | age | city          | email             | firstname
----------+-----+---------------+-------------------+-----------
Doe | 36 | Beverly Hills | janedoe@email.com | Jane (1 rows)

Updating records

To update a record in a table type the following:

UPDATE users SET city= 'San Jose' WHERE lastname= 'Doe';

The update should be available almost instantly (remember that cassandra is eventually consistent):

SELECT * FROM users where lastname= 'Doe';

 lastname | age | city     | email             | firstname
----------+-----+----------+-------------------+-----------
Doe | 36 | San Jose | janedoe@email.com | Jane (1 rows)

Deleting records

To delete a record type:

DELETE from users WHERE lastname = 'Doe';

which should result in:

SELECT * FROM users where lastname= 'Doe';

 lastname | age | city | email | firstname
----------+-----+------+-------+----------- (0 rows) SELECT * from users; lastname | age | city | email | firstname
----------+-----+------------+---------------------+-----------
Byrne | 24 | San Diego | robbyrne@email.com | Rob
Smith | 46 | Sacramento | johnsmith@email.com | John (2 rows) python cassandra客户端操作:
from cassandra.cluster import Cluster
cluster = Cluster(["10.178.204.225"])
session = cluster.connect('my_keyspace')
session.execute("""
insert into users (lastname, age, city, email, firstname) values ('Jones', 35, 'Austin', 'bob@example.com', 'Bob')
""")
result = session.execute("select * from users where lastname='Jones' ")[0]
print result.firstname, result.age session.execute("update users set age = 36 where lastname = 'Jones'")
result = session.execute("select * from users where lastname='Jones' ")[0]
print result.firstname, result.age session.execute("delete from users where lastname = 'Jones'")
result = session.execute("select * from users")
for x in result:
print x.age

参考:

https://academy.datastax.com/resources/getting-started-apache-cassandra-and-python-part-i?unit=getting-started-apache-cassandra-and-python-part-i

https://github.com/dnvriend/apache-cassandra-test/blob/master/readme.md

 

cassandra cqlsh 和 python客户端的更多相关文章

  1. Redis的Python客户端redis-py的初步使用

    1. Redis的安装 sudo pip install redis sudo pip install hiredis Parser可以控制如何解析redis响应的内容.redis-py包含两个Par ...

  2. thrift例子:python客户端/java服务端

    java服务端的代码请看上文. 1.说明: 这两篇文章其实解决的问题是,当使用python去访问大数据线上集群的时候,遇到两个问题: 1)python-hadoop和python-hive相关包链接不 ...

  3. zookeeper的python客户端安装

    项目中使用了python,需要使用到zookeeper的功能,这里记录一下安装过程. 内核版本:2.6.32 发行版:CentOs-6.6 64bit 1.由于python客户端依赖c的客户端所以要先 ...

  4. 配置百度云盘python客户端bypy上传备份文件

    要求:安装python2.7,安装git 1.git clone https://github.com/houtianze/bypy.git 2.cd bypy 3.sudo python setup ...

  5. Cassandra 数据库, python cqlsh命令

    ★  cql操作数据库(cqlsh.bat: python cqlsh命令操作<优缺点:https://blog.csdn.net/vbirdbest/article/details/77662 ...

  6. Rest Post示例(java服务端、python客户端)

    前提:服务端是现成的,java.springMVC.resttemplate.jboss等:突然有个需要,要在windows上开发一个客户端,作用是定期向服务端上传文件.想了想,如果客户端写一个jav ...

  7. python客户端编程

    上一篇说了最为底层的用来网络通讯的套接字.有很多基于套接字的一些协议,这些协议构成了当今互联网大多数客户服务器应用的核心 其实这些协议时在套接字上面的进一层封装用来完成特定的应用,这些应用主要包括: ...

  8. FFrpc python客户端lib

    摘要: Ffrpc可以很方便的构建c++ server, 在网游服务器程序开发中,进程间通讯非常的重要,比如gateserver和gameserver或dbserver之间的通信.而ffrpc可以使得 ...

  9. openstack私有云布署实践【19 通过python客户端 创建实例VM指定IP地址】

    还有一种创建方式 是使用py开发工具,调用openstackclient的方法进行创建实例 ,好处就是可随意指定我们要的虚拟机IP地址,需求的场景就是,某天我们需要主动分配一个比较熟知的IP用作某个服 ...

随机推荐

  1. Python3.6全栈开发实例[011]

    11.元素分类有如下值li= [11,22,33,44,55,66,77,88,99,90],将所有大于 66 的值保存至字典的第一个key中,将小于 66 的值保存至第二个key的值中.即: {'k ...

  2. Spring 单例

    我们知道 Web 容器本身就是多线程的,Web 容器为一个 Http 请求创建一个独立的线程,所以由此请求所牵涉到的 Spring 容器中的 Bean 也是运行于多线程的环境下.在绝大多数情况下,Sp ...

  3. LeetCode:全排列【46】

    LeetCode:全排列[46] 题目描述 给定一个没有重复数字的序列,返回其所有可能的全排列. 示例: 输入: [1,2,3] 输出: [ [1,2,3], [1,3,2], [2,1,3], [2 ...

  4. openstack ocata版(脚本)控制节点安装

    一.初始化环境: 1.更换yum源: yum install -y wget mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS- ...

  5. substring splice

    返回start到end之前 不包括end stringObject.substring(start,end) (不接受负数) stringObject.slice(start,end) start起始 ...

  6. Hibernate关联关系的CRUD

    本文以Group和User(一对多.多对一)双向关联为例,介绍关联关系的CRUD   下面先介绍两个属性 cascade:只影响CRUD中的CUD,即存储(save).更新(update).删除(de ...

  7. 计算机网络概述---OSI参考模型

    应用层:所有能产生网络流量的程序,例如:qq等,txt记事本没有产生流量,所以不属于应用层: 表示层:在传输之前对应用层的数据进行加工或处理,例如:加密.压缩.传视频时二进制,传文档时ASCII码 等 ...

  8. git基础一

    礼节为上: 从这次的武昌砍人时间分析:一定要对别人客气一点,无论在餐厅,或者任何事情上面一定要对别人客气 即使自己遇到很烦心的事情,也要保持情绪,因为如果遇到神经病,刚好自己没有控制好自己的情绪,自己 ...

  9. 发送ajax请求实现上传图片显示在网页上

    <?php // 1,通过超全局变量来获取files[上传的图片名称] $file = $_FILES["files"] // 2,在通过strrchr来获取图片的格式 $e ...

  10. 高通平台MSM8916LCM模块移植(一)-bootloader部分【转】

    本文转载自:http://www.mobile-open.com/2016/970947.html 高通平台中的bootloader叫做LK(Little Kernel,对于LCM来说LK部分相当重要 ...