How to insert a string or text as a blob in Cassandra (specifically CQLSH)

cassandracqlsh

I was trying to insert text or some string as a blob for testing purposes in CQLSH

insert into test_by_score (commit, delta, test, score)
       values (textAsBlob('bdb14fbe076f6b94444c660e36a400151f26fc6f'), 0,
       textAsBlob('{"prefix": "enwiki", "title": "\"Aghnadarragh\""}'), 100);

It didn't really work, because after I did:

select * from test_by_score where commit = 0x0b5db8b91bfdeb0a304b372dd8dda123b3fd1ab6;

its said there were 0 columns…which was a little unexpected (because it didn't throw an error at me) but I guess textAsBlob is not a thing in cqlsh. Then does someone know how to do this?

Schema:

CREATE TABLE IF NOT EXISTS test_by_score (
    commit blob, 
    delta int, 
    score int, 
    test blob, 
    PRIMARY KEY(commit, delta, test)
);

I have posted my schema a little reluctantly because I believe my question is not really about this specific schema. What I simply want to to know is, if there is one column that holds blobs, is it possible to insert a string in that position by first changing it to a blob and then inserting it in cqlsh?

Best Answer

The following seems to be working. Your WHERE condition in your SELECT statement may be trying to access the incorrect hex 0x0b5db8b91bfdeb0a304b372dd8dda123b3fd1ab6. 

DROP KEYSPACE example;
CREATE KEYSPACE example WITH replication = {'class':'SimpleStrategy', 'replication_factor':1};
USE example;

CREATE TABLE IF NOT EXISTS test_by_score (
    commit blob, -- blob representing the commit hash
    delta int, -- how much the scores have changed
    score int, -- the test score, which is determined by the client
    test blob, -- blob for the test
    PRIMARY KEY(commit, delta, test)
);

INSERT INTO test_by_score  (commit, delta, test, score) VALUES 
  (textAsBlob('bdb14fbe076f6b94444c660e36a400151f26fc6f'), 0, textAsBlob('{"prefix": "enwiki", "title": "\"Aghnadarragh\""}'), 100
);

INSERT INTO test_by_score (commit, delta, test, score) VALUES (
  textAsBlob('cdb14fbe076f6b94444c660e36a400151f26fc6f'), 0, textAsBlob('{"prefix": "enwiki", "title": "\"Aghnadarragh\""}'), 100
);

INSERT INTO test_by_score (commit, delta, test, score) VALUES (
  textAsBlob('adb14fbe076f6b94444c660e36a400151f26fc6f'), 0, textAsBlob('{"prefix": "enwiki", "title": "\"Aghnadarragh\""}'), 100
);

To grab all the rows

SELECT * FROM example.test_by_score

To select a specific row.

SELECT * FROM example.test_by_score 
  WHERE commit = 0x62646231346662653037366636623934343434633636306533366134303031353166323666633666;
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