Re: Add column if it does not exist?

To hop on what Jon said, if your concern is automatic application of schema migrations, you want to be very careful with this. I'd consider it an unsolved problem in Cassandra for some methods of schema application. The failed ALTER is not what you have to worry about, it's two successful ALTERs

Re: Add column if it does not exist?

Yah. I saw one such migration via Spark Job running concurrently and created 4 Cfids and migrated data. It was a nightmare to cleanup the duplicated sstables. Alter schema and migrate should always be different applications separate from the actual system. -- Rahul Singh rahul.si...@anant.us

Re: Add column if it does not exist?

All of the drivers also have keyspace / table metadata. For instance: https://datastax.github.io/python-driver/api/cassandra/metadata.html I’d be *really* careful how you use this. A lot of teams want to just deploy their

Re: Add column if it does not exist?

Hello, this link might also be helpful to you for querying table schema. Link: https://docs.datastax.com/en/cql/3.3/cql/cql_using/useQuerySystemTable.html Best, Iriiza On Tue, Feb 6, 2018 at 9:55 PM, Oliver Ruebenacker wrote: > > Hello, > > Is there a describe

Re: Add column if it does not exist?

Yes describe query is available cqlsh. Try the example given below: Example: cqlsh> describe keyspaceName.tableName; It will return the schema of the table. On 6 Feb 2018 21:55, "Oliver Ruebenacker" wrote: > > Hello, > > Is there a describe query in CQL? I don't see

Re: Add column if it does not exist?

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 wrote: > Hello. >

Re: Add column if it does not exist?

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" wrote: > Thanks for the response! > >

Re: Add column if it does not exist?

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

Re: Add column if it does not exist?

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 , wrote: > Well, it does throw an InvalidQueryException if the column already exists.

Re: Add column if it does not exist?

Well, it does throw an InvalidQueryException if the column already exists. On Mon, Feb 5, 2018 at 4:44 PM, Rahul Singh 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. > > -- >

Re: Add column if it does not exist?

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 , wrote: > > Hello, > >   What's the

Add column if it does not exist?

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 , Broad Institute