Import CSV with multi-valued (collection) attributes to Cassandra

Question

Suppose I would like to import a csv file into the following table:

CREATE TABLE example_table (
  id int PRIMARY KEY,
  comma_delimited_str_list list

        

Answer 1

CQL 1.2 is able to port CSV file with multi-valued fields directly to a table. However, the format of those multi-valued fields must match the CQL format.

For example, lists must be in the form ['abc','def','ghi'], and sets must be in the form {'123','456','789'}.

Below is an example of importing CSV formatted data to the example_table mentioned in the OP from STDIN:

cqlsh:demo> copy example_table from STDIN;
[Use \. on a line by itself to end input]
[copy] 12345,"['hello','world']","['stack','overflow']"
[copy] 56780,"['this','is','a','test','list']","['here','is','another','one']"
[copy] \.

2 rows imported in 11.304 seconds.
cqlsh:demo> select * from example_table;

 id    | comma_delimited_str_list  | space_delimited_str_list
-------+---------------------------+--------------------------
 12345 |            [hello, world] |        [stack, overflow]
 56780 | [this, is, a, test, list] | [here, is, another, one]

Importing incorrect formatted list or set values from a CSV file will raise an error:

cqlsh:demo> copy example_table from STDIN;
[Use \. on a line by itself to end input]
[copy] 9999,"hello","world"
Bad Request: line 1:108 no viable alternative at input ','
Aborting import at record #0 (line 1). Previously-inserted values still present.

The above input should be replaced by 9999,"['hello']","['world']":

cqlsh:demo> copy example_table from STDIN;
[Use \. on a line by itself to end input]
[copy] 9999,"['hello']","['world']"
[copy] \.

1 rows imported in 16.859 seconds.
cqlsh:demo> select * from example_table;

 id    | comma_delimited_str_list  | space_delimited_str_list
-------+---------------------------+--------------------------
  9999 |                   [hello] |                  [world]
 12345 |            [hello, world] |        [stack, overflow]
 56780 | [this, is, a, test, list] | [here, is, another, one]