amazon-web-servicescassandracqlamazon-keyspaces

Is it possible to drop a column from AWS Keyspaces table?


I need to write roll-in and roll-back scripts for AWS Keyspaces. Roll-in is

ALTER TABLE my_table ADD (
  next_value_1 double,
  next_value_2 double,
);

What roll-back script should be? According to what's written at Tutorial: Delete data in an Amazon Keyspaces table I can't drop columns from a table.

You can delete a column from a specific row, individual rows from a table, all the rows from a table, an entire table, or a keyspace.

Also there's no ALTER TABLE xxx DROP () mentions in DDL statements page.

Is there any way to do this?


Solution

  • It looks like you cannot. From the doc mentioned in the original post, the supported syntax is:

    ALTER TABLE table_name    
    
        [ ADD ( column_definition | column_definition_list)  ] 
        [[ADD | DROP] TAGS {'key1':'val1', 'key2':'val2'}]            
        [ WITH table_options [ , ... ] ] ;
    

    It looks like you can ADD and DROP tags, but you can only ADD columns. If you need to DROP a column, it looks like you'll have to recreate the table.

    Despite how AWS Keyspaces is touted as a drop-in replacement for Cassandra, there are many things that it simply does not support.

    Note that ALTER TABLE table_name DROP column_name does indeed work in both Apache Cassandra and DataStax Astra DB.