问题描述
有没有一种简单的方法来检查是否在Cassandra中使用CQL（或API，也许使用com.datastax.driver）定义表（列族）？
Is there an easy way to check if table (column family) is defined in Cassandra using CQL (or API perhaps, using com.datastax.driver)?
现在我倾向于执行 SELECT 1 FROM table 并检查异常，但也许有更好的方法？
Right now I am leaning towards executing SELECT 1 FROM table and checking for exception but maybe there is a better way?
推荐答案
从1.1开始，您应该可以查询系统键空间， schema_columnfamilies 列族。如果您知道要检查哪个键空间，此CQL应列出键空间中的所有列族：
As of 1.1 you should be able to query the system keyspace, schema_columnfamilies column family. If you know which keyspace you want to check, this CQL should list all column families in a keyspace:
SELECT columnfamily_name
FROM schema_columnfamilies WHERE keyspace_name='myKeyspaceName';
描述此功能的报告如下：
The report describing this functionality is here: https://issues.apache.org/jira/browse/CASSANDRA-2477
虽然，他们确实注意到一些系统列名称已在1.1和1.2之间更改。
Although, they do note that some of the system column names have changed between 1.1 and 1.2. So you might have to mess around with it a little to get your desired results.
编辑20160523 - Cassandra 3.x更新：
请注意，对于Cassandra 3.0及以上版本，您需要对上述查询进行一些调整：
Note that for Cassandra 3.0 and up, you'll need to make a few adjustments to the above query:
SELECT table_name
FROM system_schema.tables WHERE keyspace_name='myKeyspaceName';
这篇关于如何检查Cassandra表是否存在的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！