alter cassandra CQL 3.0中的复合主键

问题描述

我遇到需要更改复合主键的情况，如下所示：

旧主键：（id，source，attribute_name ，updated_at）;

我想要的新主键：（source，id，attribute_name，updated_at）;

我发出了以下命令（mysql like）：

  ALTER TABLE general_trend_table 
 DROP PRIMARY KEY，
 ADD PRIMARY KEY（source，id，attribute_name，updated_at）; 
  

我收到以下错误：

错误请求：第1:38行在输入PRIMARY中无可行替代

任何想法如何解决此问题？更具体地说，我想知道是否有任何方法可以更改cassandra中的主键？

解决方案

您可以使用新的主键创建一个新表，从旧的主键复制数据，然后删除旧表。

I'm in a situation where I need to change the the composite primary key as follows:

Old Primary Key: (id, source, attribute_name, updated_at);

New Primary Key I want: (source, id, attribute_name, updated_at);

I issued the following (mysql like) command:

ALTER TABLE general_trend_table
DROP PRIMARY KEY,
ADD PRIMARY KEY(source, id, attribute_name, updated_at);

I got the following error:

Bad Request: line 1:38 no viable alternative at input 'PRIMARY'

any idea how to get around this problem? more specifically I want to know is there any way to change the primary key in cassandra?

解决方案

There is no way to change a primary key, as it defines how your data is physically stored.

You can create a new table with the new primary key, copy data from the old one, and then drop the old table.

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