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From: "Hiller, Dean" <Dean.Hiller@nrel.gov>
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Date: Tue, 24 Sep 2013 11:24:19 -0600
Subject: =?iso-8859-2?Q?Re:_is_this_correct,_thrift_unportable_to_CQL3=A9.?=
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Message-ID: <CE672695.32785%Dean.Hiller@nrel.gov>
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Java has Integer as opposed to int which is what I represent "golf scores" =
with so to speak in my example.  In this case, Integer can be null but of c=
ourse maps to "empty" just fine.  What about querying for all golf scores t=
hat are "empty" then?

Ie. This sounds like this solution would be perfect if we can get rid of th=
e exception piece.

Thanks much!!!
Dean

From: Sylvain Lebresne <sylvain@datastax.com<mailto:sylvain@datastax.com>>
Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <us=
er@cassandra.apache.org<mailto:user@cassandra.apache.org>>
Date: Tuesday, September 24, 2013 10:58 AM
To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cas=
sandra.apache.org<mailto:user@cassandra.apache.org>>
Subject: Re: is this correct, thrift unportable to CQL3=A9.

On Tue, Sep 24, 2013 at 6:17 PM, Vikas Goyal <vikas@easility.com<mailto:vik=
as@easility.com>> wrote:
Ok. Great. It works for String and Decimal/Float but not for integer data t=
ype..
i.e,, if I am passing "" to the composite key column which is either text o=
r float, it works..

session.execute(boundStatement.bind(rowkey, "", ByteBuffer.wrap(value)));

But not working with bigint, int or varint..and getting following exception=
;

Exception:Invalid type for value 1 of CQL type varint, expecting class java=
.math.BigInteger but class java.lang.String provided

..I am exploring more though..

We're getting into details of the java driver at this point. For int, what =
you can do is:
  boundStatement.setString("id", rowkey);
  boundStatement.setBytesUnsafe("columnname", ByteBuffer.wrap(new byte[0]))=
;
  boundStatement.setBytes("columnvalue", ByteBuffer.wrap(value));

In other words, the shorthand BoundStatement.bind() won't let you insert an=
 empty value for types
that don't naturally have an empty value (like int; keep in mind that an em=
pty value is not the same
than null). But you can circumvent that using setBytesUnsafe if you really =
want.

Long story short, my advice would be to avoid using empty values for type t=
hat don't naturally have
one (anything else than text and blob really). If you do, that's going to b=
e painful (but possible) to
work with, at least with the java driver (but for good reasons, java just d=
oesn't have a good to
represent an empty int value (again, you can have a null Integer but that's=
 different)).

--
Sylvain


Thanks a ton,
Vikas Goyal


On Tue, Sep 24, 2013 at 9:05 PM, Sylvain Lebresne <sylvain@datastax.com<mai=
lto:sylvain@datastax.com>> wrote:

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 nul=
l..else 2 values..

            if (key !=3D null) {
                PreparedStatement statement =3D session.prepare("INSERT INT=
O keys.StringIndice (id, colname, colvalue) VALUES (?, ?, ?)");
                BoundStatement boundStatement =3D new BoundStatement(statem=
ent);
                session.execute(boundStatement.bind(StandardConverters.conv=
ertFromBytes(String.class, rowKey), key, ByteBuffer.wrap(value)));
            } else {
                PreparedStatement statement =3D session.prepare("INSERT INT=
O " + keys + "." + table + "(id, colvalue) VALUES (?, ?)");
                BoundStatement boundStatement =3D new BoundStatement(statem=
ent);
                session.execute(boundStatement.bind(StandardConverters.conv=
ertFromBytes(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<mai=
lto:sylvain@datastax.com>> wrote:
Short answer: not, this is not correct.

Longer answer: what you call "null" is actually an empty value (which is *n=
ot* the same thing, unless you consider an empty string is the same thing t=
han a null string). As it happens, C* always an empty value as a valid valu=
e for any type and that's true of both thrift and CQL3. What is true is tha=
t CQL3 discourage the use of empty values for type for which it doesn't par=
ticularly make sense (integers typically) by not having a particular easy t=
o 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 wa=
nt to use a prepared statement, CQL3 has conversion functions (http://cassa=
ndra.apache.org/doc/cql3/CQL.html#blobFun) that allows to do it (for instan=
ce, "blobAsInt(0x)" will be an empty int value).

--
Sylvain


On Tue, Sep 24, 2013 at 2:36 PM, Hiller, Dean <Dean.Hiller@nrel.gov<mailto:=
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 s=
core : 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 quit=
e 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-col=
umn-value-for-a-composite-key-column-in-cql3

(This sounds like a major deficit to me as the wide row now can only be use=
d where actual values exist?????).  Is it possible to port this pattern to =
CQL3?

Thanks,
Dean