Hello,
Is there a describe query in CQL? I don't see one on
http://cassandra.apache.org/doc/latest/cql/index.html.
I also can't find such a query in the DataStax Java driver API.
Thanks!
Best, Oliver
On Tue, Feb 6, 2018 at 11:48 AM, Irtiza Ali <i...@an10.io> wrote:
> Hello.
>
> Another thing that you can try is the use the describe table query to get
> the table schema and parse it. Once done you can check whether column
> exists or not.
>
>
> With Regards
> Irtiza Ali
>
> On 6 Feb 2018 21:35, "Oliver Ruebenacker" <cur...@gmail.com> wrote:
>
>> Thanks for the response!
>>
>> So, the best solution I can come up with is catching the
>> InvalidQueryException and check whether its message contains the phrase
>> "conflicts with an existing column". Seems to work, but super-ugly.
>>
>> I do assume that in general, if a request fails, it does not
>> permanently change the data in Cassandra, right?
>>
>> It would be great if alter-add could have an if-not-exists clause.
>> Would that be hard to implement?
>>
>> I could not find a standard CQL way of asking what columns exist. Did I
>> miss it? Would it be hard to implement?
>>
>> I get that we're only eventually consistent anyway.
>>
>> Thanks!
>>
>> Best, Oliver
>>
>> On Mon, Feb 5, 2018 at 5:12 PM, Rahul Singh <rahul.xavier.si...@gmail.com
>> > wrote:
>>
>>> Yeah, you can handle the exception — what i meant that it wouldnt cause
>>> harm to the DB
>>>
>>> --
>>> Rahul Singh
>>> rahul.si...@anant.us
>>>
>>> Anant Corporation
>>>
>>> On Feb 5, 2018, 5:07 PM -0500, Oliver Ruebenacker <cur...@gmail.com>,
>>> wrote:
>>>
>>> Well, it does throw an InvalidQueryException if the column already
>>> exists.
>>>
>>> On Mon, Feb 5, 2018 at 4:44 PM, Rahul Singh <
>>> rahul.xavier.si...@gmail.com> wrote:
>>>
>>>> Since CQL != SQL, there’s isnt a syntatical way. Just run the alter
>>>> table command and it shouldn't be an issue if its there.
>>>>
>>>> --
>>>> Rahul Singh
>>>> rahul.si...@anant.us
>>>>
>>>> Anant Corporation
>>>>
>>>> On Feb 5, 2018, 4:15 PM -0500, Oliver Ruebenacker <cur...@gmail.com>,
>>>> wrote:
>>>>
>>>>
>>>> Hello,
>>>>
>>>> What's the easiest way to add a column to a table but only if it does
>>>> not exist? Thanks!
>>>>
>>>> Best, Oliver
>>>>
>>>> --
>>>> Oliver Ruebenacker
>>>> Senior Software Engineer, Diabetes Portal
>>>> <http://www.type2diabetesgenetics.org/>, Broad Institute
>>>> <http://www.broadinstitute.org/>
>>>>
>>>>
>>>
>>>
>>> --
>>> Oliver Ruebenacker
>>> Senior Software Engineer, Diabetes Portal
>>> <http://www.type2diabetesgenetics.org/>, Broad Institute
>>> <http://www.broadinstitute.org/>
>>>
>>>
>>
>>
>> --
>> Oliver Ruebenacker
>> Senior Software Engineer, Diabetes Portal
>> <http://www.type2diabetesgenetics.org/>, Broad Institute
>> <http://www.broadinstitute.org/>
>>
>>
--
Oliver Ruebenacker
Senior Software Engineer, Diabetes Portal
<http://www.type2diabetesgenetics.org/>, Broad Institute
<http://www.broadinstitute.org/>
