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>> > Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" > <user@cassandra.apache.org<mailto: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<mailto: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>> 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 >> >> >
