如何在cassandra中定义动态列族 [英] How to define dynamic column families in cassandra

问题描述

这里是说，没有特殊的努力需要得到一个动态列族。但我总是得到一个异常，当我尝试为一个未定义的列设置一个值。

Here it is said, that no special effort is need to get a dynamic column family. But I always get an exception, when I try to set a value for an undefined column.

我创建了一个这样的列族：

I created a column family like this:

CREATE TABLE places (
   latitude double,
   longitude double,
   name text,
   tags text,
   PRIMARY KEY (latitude, longitude, name)
)

定义标签列。有人可以解释我为什么吗？也许是因为所有其他列都是索引的一部分？

BTW: I had to define the tags column. Can somebody explain me why? Maybe because all other columns are part of the Index?

现在当插入如下数据时：

Now when inserting data like this:

INSERT INTO places ("latitude","longitude","name","tags") VALUES (49.797888,9.934771,'Test','foo,bar')

它工作正常！但是当我尝试时：

it works just fine! But when I try:

INSERT INTO places ("latitude","longitude","name","tags","website") VALUES (49.797888,9.934771,'Test','foo,bar','test.de')

$ b b

我得到以下错误：

I get following error:

Bad Request: Unknown identifier website
text could not be lexed at line 1, char 21

需要进行哪些更改才能动态添加列？

Which changes are needed so I can dynamically add columns?

我使用Cassandra 1.1.9和CQL3直接在服务器上使用cqlsh。

I am using Cassandra 1.1.9 with CQL3 with the cqlsh directly on a server.

推荐答案

CQL3支持动态列族，但是你必须先修改表格模式

CQL3 supports dynamic column family but you have to alter the table schema first

ALTER TABLE places ADD website varchar;

查看 1.2文档和 CQL深入幻灯片

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