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From Sylvain Lebresne <sylv...@datastax.com>
Subject Re: is this correct, thrift unportable to CQL3Š.
Date Tue, 24 Sep 2013 15:35:16 GMT
> However,we tried missing the value but it didn't work :(
>

Right, because not providing a value is akin to having a null value (in the
CQL3 sense of the term, which is different from what Dean asked about) and
null values are not allowed for primary key columns.
You could however insert an *empty* value if you wanted, which in you case
is just inserting an empty string since colname is a string. Thrift doesn't
allow more or less in that case.

--
Sylvain



>
> So our code is like below where we are using 3 values if colname is not
> null..else 2 values..
>
>             if (key != null) {
>                 PreparedStatement statement = session.prepare("INSERT INTO
> keys.StringIndice (id, colname, colvalue) VALUES (?, ?, ?)");
>                 BoundStatement boundStatement = new
> BoundStatement(statement);
>
> session.execute(boundStatement.bind(StandardConverters.convertFromBytes(String.class,
> rowKey), key, ByteBuffer.wrap(value)));
>             } else {
>                 PreparedStatement statement = session.prepare("INSERT INTO
> " + keys + "." + table + "(id, colvalue) VALUES (?, ?)");
>                 BoundStatement boundStatement = new
> BoundStatement(statement);
>
> session.execute(boundStatement.bind(StandardConverters.convertFromBytes(String.class,
> rowKey), ByteBuffer.wrap(value)));
>           }
>
> And, I did that and getting this exception:
>
> Exception:Missing PRIMARY KEY part colname since colvalue is set
>
> And just FYI. Our Column Family definition is below:
>
> CREATE TABLE keys.StringIndice (id text,
> colname text,
>  colvalue blob,
> PRIMARY KEY (id,colname, colvalue)) WITH COMPACT STORAGE)
>
> Thanks again,
> Vikas Goyal
>
>
>
> On Tue, Sep 24, 2013 at 7:02 PM, Sylvain Lebresne <sylvain@datastax.com>wrote:
>
>> Short answer: not, this is not correct.
>>
>> Longer answer: what you call "null" is actually an empty value (which is
>> *not* the same thing, unless you consider an empty string is the same thing
>> than a null string). As it happens, C* always an empty value as a valid
>> value for any type and that's true of both thrift and CQL3. What is true is
>> that CQL3 discourage the use of empty values for type for which it doesn't
>> particularly make sense (integers typically) by not having a particular
>> easy to use syntax to input them. But that's supported nonetheless. If you
>> use a prepared statement for instance (where you send values already
>> serialized), nothing will prevent you from sending an empty value. Even if
>> you don't want to use a prepared statement, CQL3 has conversion functions (
>> http://cassandra.apache.org/doc/cql3/CQL.html#blobFun) that allows to do
>> it (for instance, "blobAsInt(0x)" will be an empty int value).
>>
>> --
>> Sylvain
>>
>>
>>
>> On Tue, Sep 24, 2013 at 2:36 PM, Hiller, Dean <Dean.Hiller@nrel.gov>wrote:
>>
>>> Many applications in thrift use the wide row with composite column name
>>> and as an example, let's say golf score for instance and we end up with
>>> golf score : pk like so
>>>
>>> null : pk56
>>> null : pk45
>>> 89 : pk90
>>> 89: pk87
>>> 90: pk101
>>> 95: pk17
>>>
>>> Notice that there are some who do not have a golf score(zero would not
>>> quite make sense and would be interpreted as a golf score).  I am hearing
>>> from this post if they are correct that this is not portable to CQL3???  Is
>>> this true?
>>> http://stackoverflow.com/questions/18963248/how-can-i-have-null-column-value-for-a-composite-key-column-in-cql3
>>>
>>> (This sounds like a major deficit to me as the wide row now can only be
>>> used where actual values exist?????).  Is it possible to port this pattern
>>> to CQL3?
>>>
>>> Thanks,
>>> Dean
>>>
>>>
>>>
>>
>

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