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Re: Apache Cassandra and BIRT [message #808482 is a reply to message #806380] |
Mon, 27 February 2012 20:45 |
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That is most likely the issue. The JDBC driver needs to support meta
data. Another option would be to just use a scripted data source and
call it like you were calling any external Java class.
Jason
On 2/24/2012 5:40 PM, tbee wrote:
>> If I set this JDBC driver up in BIRT, the "test connection" on the
>> Data Source works fine. I can also create a Data Set, but there are no
>> output columns. Also if I just do a "select KEY from InstanceLicense".
>> What is the JDBC driver not doing right?
>
> After doing some research; is BIRT accessing the resultset's metadata
> before fetching the first row? Cassandra has no database schedule, so it
> must derive the meta data from the actual values.
>
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Re: Apache Cassandra and BIRT [message #809420 is a reply to message #808921] |
Tue, 28 February 2012 21:24 |
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Did you get this to work? If so I would love to see a blog post on it.
Jason
On 2/28/2012 4:39 AM, tbee wrote:
> I've patched Cassandra's JDBC driver to do a read ahead when getMetadata
> is done before the first row of data is read. The problem with Cassandra
> is that it does not have a database schema, only collections of
> key-value pairs, and therefore each row may have different contents.
>
> In real life use this turns out not to be such a big issue, since one
> usually writes the same values in each row, but it does require a row to
> be fetched in order to determine what columns are available.
>
> Patched. Thanks!
>
> Tom
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