I see, it helps a lot. Thank you for you info. Oh, also Mr. Joe Celko :P
On Thu, Oct 18, 2012 at 7:10 PM, aaron morton <aa...@thelastpickle.com>wrote: > Very slim reason to link to my favourite Joe Celko ( > http://en.wikipedia.org/wiki/Joe_Celko) quote: > > " > 'LOL! My wife is an ordained Soto Zen priest. I would say after 30 years > together, I'd go with her. She is the only person who understood NULLs > immediately. > > http://www.simple-talk.com/opinion/geek-of-the-week/geek-of-the-week-joe-celko/ > " > > a. A row which has only key without columns > > b. No this row in database. > > From the point of view of the API a row with zero *live* columns is the > same as a row that does not exist. > > A row may exist on disk, but be made up of non-live columns. These are a > combination of expired TTL columns and columns overwritten by (row or > column) tombstones. Eventually a row with 0 live columns, with >0 non live > columns will be compacted and purged from disk. > > Hope that helps. > > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 18/10/2012, at 1:34 AM, "Hiller, Dean" <dean.hil...@nrel.gov> wrote: > > What specifically are you trying to achieve? The business requirement > might help as there are other ways of solving it such that you do not need > to know the difference. > > Dean > > From: Xu Renjie > <xrjxrjxrj...@gmail.com<mailto:xrjxrjxrj...@gmail.com<xrjxrjxrj...@gmail.com> > >> > Reply-To: > "user@cassandra.apache.org<mailto:user@cassandra.apache.org<user@cassandra.apache.org>>" > <user@cassandra.apache.org<mailto:user@cassandra.apache.org<user@cassandra.apache.org> > >> > Date: Wednesday, October 17, 2012 4:48 AM > To: > "user@cassandra.apache.org<mailto:user@cassandra.apache.org<user@cassandra.apache.org>>" > <user@cassandra.apache.org<mailto:user@cassandra.apache.org<user@cassandra.apache.org> > >> > Subject: Re: Astyanax empty column check > > So what you mean is essentially there is *no* way to differentiate it > because what they "appear" is the same? > > On Wed, Oct 17, 2012 at 5:58 PM, rohit bhatia <rohit2...@gmail.com< > mailto:rohit2...@gmail.com <rohit2...@gmail.com>>> wrote: > See > "If you attempt to retrieve an entire row and it returns a result with > no columns, it effectively means that row does not exist." > Essentially a row without co > > > http://stackoverflow.com/questions/8072253/is-there-a-difference-between-an-empty-key-and-a-key-that-doesnt-exist > > lumns doesn't exist.. (except those with tombstones) > from here > On Wed, Oct 17, 2012 at 2:17 PM, Xu Renjie <xrjxrjxrj...@gmail.com<mailto: > xrjxrjxrj...@gmail.com>> wrote: > > Sorry for the version, I am using 1.0.1 Astyanax. > > > On Wed, Oct 17, 2012 at 4:44 PM, Xu Renjie <xrjxrjxrj...@gmail.com<mailto: > xrjxrjxrj...@gmail.com>> wrote: > > > hello guys, > I am currently using Astyanax as a client(new to Astyanax). But I am > not clear how to differentiate the following 2 situations: > a. A row which has only key without columns > b. No this row in database. > > Since when I use RowQuery to query Cassandra with given key, both the > above two situations will return a ColumnList > with size 0. And also I didn't find other api can handle this. > Do you have any better way for this? Thanks in advance. > Cheers, > Xu > > > > > >
