Re: Deleting column names

[Andreas Wagner]

Thanks :) This works ...

Kind regards
Andreas


On 04/22/2014 06:05 PM, Laing, Michael wrote:
Your understanding is incorrect - the easiest way to see that is to 
try it.



On Tue, Apr 22, 2014 at 12:00 PM, Sebastian Schmidt > wrote:


From my understanding, this would delete all entries with the
given s. Meaning, if I have inserted (sa, p1, o1, c1) and (sa, p2,
o2, c2), executing this:

DELETE FROM table_name WHERE s = sa AND p = p1 AND o = o1 AND c = c1

would delete sa, p1, o1, c1, p2, o2, c2. Is this correct? Or does
the above statement only delete p1, o1, c1?


2014-04-22 4:00 GMT+02:00 Steven A Robenalt mailto:srobe...@stanford.edu>>:

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
mailto:eric.pl...@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
mailto:andreas.josef.wag...@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

srobe...@stanford.edu 
http://highwire.stanford.edu

/
/

Re: Deleting column names

[Laing, Michael]

Your understanding is incorrect - the easiest way to see that is to try it.


On Tue, Apr 22, 2014 at 12:00 PM, Sebastian Schmidt wrote:

> From my understanding, this would delete all entries with the given s.
> Meaning, if I have inserted (sa, p1, o1, c1) and (sa, p2, o2, c2),
> executing this:
>
> DELETE FROM table_name WHERE s = sa AND p = p1 AND o = o1 AND c = c1
>
> would delete sa, p1, o1, c1, p2, o2, c2. Is this correct? Or does the
> above statement only delete p1, o1, c1?
>
>
> 2014-04-22 4:00 GMT+02:00 Steven A Robenalt :
>
> 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  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.wag...@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
>>
>> srobe...@stanford.edu
>> http://highwire.stanford.edu
>>
>>
>>
>>
>>
>>
>

Re: Deleting column names

[Sebastian Schmidt]

>From my understanding, this would delete all entries with the given s.
Meaning, if I have inserted (sa, p1, o1, c1) and (sa, p2, o2, c2),
executing this:

DELETE FROM table_name WHERE s = sa AND p = p1 AND o = o1 AND c = c1

would delete sa, p1, o1, c1, p2, o2, c2. Is this correct? Or does the above
statement only delete p1, o1, c1?


2014-04-22 4:00 GMT+02:00 Steven A Robenalt :

> 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  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.wag...@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
>
> srobe...@stanford.edu
> http://highwire.stanford.edu
>
>
>
>
>
>

Re: Deleting column names

[Laing, Michael]

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
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  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.wag...@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
>
> srobe...@stanford.edu
> http://highwire.stanford.edu
>
>
>
>
>
>

Re: Deleting column names

[Steven A Robenalt]

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  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.wag...@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

srobe...@stanford.edu
http://highwire.stanford.edu

Re: Deleting column names

[Eric Plowe]

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.wag...@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
>>
>
>

Re: Deleting column names

[Eric Plowe]

Setting the columns to null is essentially deleting them from my
understanding. A delete operation works on the entire row.

On Monday, April 21, 2014, Andreas Wagner <
andreas.josef.wag...@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
>>
>
>

Re: Deleting column names

[Andreas Wagner]

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