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From "Laing, Michael" <michael.la...@nytimes.com>
Subject Re: Deleting column names
Date Tue, 22 Apr 2014 11:09:45 GMT
Referring to the original post, I think the confusion is what is a "row" in
this context:

So as far as I understand, the s column is now the *row *key

...

Since I have multiple different p, o, c combinations per s, deleting the whole
> *row* identified by s is no option


The s column is in fact the *partition_key*, not the row key, which is the
composite of all 4 columns (the partiton_key plus the clustering columns).

Deleting the row, as Steven correctly showed, will not delete the
partition, but only the row - the tuple of the 4 columns.

Terminology has changed with cql and we all have to get used to it.

ml


On Mon, Apr 21, 2014 at 10:00 PM, Steven A Robenalt
<srobenal@stanford.edu>wrote:

> Is there a reason you can't use:
>
> DELETE FROM table_name WHERE s = ? AND p = ? AND o = ? AND c = ?;
>
>
> On Mon, Apr 21, 2014 at 6:51 PM, Eric Plowe <eric.plowe@gmail.com> wrote:
>
>> Also I don't think you can null out columns that are part of the primary
>> key after they've been set.
>>
>>
>> On Monday, April 21, 2014, Andreas Wagner <
>> andreas.josef.wagner@googlemail.com> wrote:
>>
>>> Hi cassandra users, hi Sebastian,
>>>
>>> I'd be interested in this ... is there any update/solution?
>>>
>>> Thanks so much ;)
>>> Andreas
>>>
>>> On 04/16/2014 11:43 AM, Sebastian Schmidt wrote:
>>>
>>>> Hi,
>>>>
>>>> I'm using a Cassandra table to store some data. I created the table like
>>>> this:
>>>> CREATE TABLE IF NOT EXISTS table_name (s BLOB, p BLOB, o BLOB, c BLOB,
>>>> PRIMARY KEY (s, p, o, c));
>>>>
>>>> I need the at least the p column to be sorted, so that I can use it in a
>>>> WHERE clause. So as far as I understand, the s column is now the row
>>>> key, and (p, o, c) is the column name.
>>>>
>>>> I tried to delete single entries with a prepared statement like this:
>>>> DELETE p, o, c FROM table_name WHERE s = ? AND p = ? AND o = ? AND c =
>>>> ?;
>>>>
>>>> That didn't work, because p is a primary key part. It failed during
>>>> preparation.
>>>>
>>>> I also tried to use variables like this:
>>>> DELETE ?, ?, ? FROM table_name WHERE s = ?;
>>>>
>>>> This also failed during preparation, because ? is an unknown identifier.
>>>>
>>>>
>>>> Since I have multiple different p, o, c combinations per s, deleting the
>>>> whole row identified by s is no option. So how can I delete a s, p, o, c
>>>> tuple, without deleting other s, p, o, c tuples with the same s? I know
>>>> that this worked with Thrift/Hector before.
>>>>
>>>> Regards,
>>>> Sebastian
>>>>
>>>
>>>
>
>
> --
> Steve Robenalt
> Software Architect
> HighWire | Stanford University
> 425 Broadway St, Redwood City, CA 94063
>
> srobenal@stanford.edu
> http://highwire.stanford.edu
>
>
>
>
>
>

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