什么是ApacheCassandra中的DML？

我计划为开发人员提供DataStax Cassandra认证.我最近参加了练习测试,我得到了94%的100分,其中1个答案标记错误.问题是:

Given the following table, which of the following statements is an example of 
Data Modification Language (DML) in CQL? CREATE TABLE comics ( title text, 
issueNumber int, originalPriceDollars float, PRIMARY KEY ( title, issueNumber 
) );

SELECT * FROM comics;
ALTER TABLE comics ADD currentPriceDollars float;
DROP KEYSPACE test;
None of the other answers are DML.

我选择了ALTER TABLE漫画选项,根据DataStax,这个答案是错误的.那么什么是Cassandra的DML.这句话是不是修改了数据？而且,正确的答案是无.

谢谢.