Unable to remove key\value pair from map column in cassandra

[hemabs]

Hi,

From the link below:

http://www.datastax.com/drivers/java/1.0/com/datastax/driver/core/querybuilder/QueryBuilder.html

I am able to figure out add and remove for list and set:

Set: addAll, removeAll

List: appendAll, discardAll

Map: putAll

What is the equivalent remove method for a map to remove key/value pair from the map column.

Is this not provided by the Cassandra API?

Thanks

[Olivier Michallat]

Hi,

The CQL syntax to delete from a map is:

    DELETE m['key'] FROM foo WHERE k=1

The equivalent with QueryBuilder is:

    delete().mapElt("m", "key").from("foo").where(eq("k", 1));

--

Olivier Michallat

Driver & tools engineer, DataStax

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[hemabs]

Thanks Olivier. Is there any other way of doing it? I did not wanted to use the raw delete statement or QueryBuilder that uses delete function.

[Olivier Michallat]

Not that I'm aware of. Maps don't support the "delete with update" syntax that sets have (UPDATE foo  SET s = s - {e} ...). I don't know if there's a good reason for that, you can ask on the Cassandra user mailing list if you want more details.

--

Olivier Michallat

Driver & tools engineer, DataStax

[hemabs]

Thank you Olivier. Appreciate it.

[DuyHai Doan]

Or you can do

UPDATE  foo SET m['key'] = null WHERE k=1

Setting null means deleting in CQL, at least for now, it may change in the future

[hemabs]

Thanks DuyHai for the help.