Cassandra - 对行键的唯一约束 [英] Cassandra - unique constraint on row key

问题描述

我想知道，只要Cassandra可以在行键上指定唯一约束。类似于SQL Server的 ADD CONSTRAINT myConstrain UNIQUE（ROW_PK）

I would like to know whenever it is possible in Cassandra to specify unique constrain on row key. Something similar to SQL Server's ADD CONSTRAINT myConstrain UNIQUE (ROW_PK)

如果插入已存在的行键，现有的数据将不会被覆盖，但是我收到一些异常或响应，由于约束违反而不能执行更新。

In case of insert with already existing row key, the existing data will be not overwritten, but I receive kind of exception or response that update cannot be performed due to constrain violation.

也许这个问题有一个解决方法 - 有更新接缝为原子的计数器

Maybe there is a workaround for this problem - there are counters which updates seams to be atomic

感谢，

Maciej

推荐答案

一种可能性是使用Cages和ZooKeeper：

One possibility is to use Cages and ZooKeeper:

http://ria101.wordpress.com/2010/05/12/locking-和

http://ria101.wordpress.com/2010/05/12/locking-and-transactions-over-cassandra-using-cages

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