On 24 Jun 2014, at 11:50, Gunnar Morling <gunnar(a)hibernate.org> wrote:
Yes, today we don't.
But is there any reason for not using the value column name?
Not more that the ones I outlined in this thread.
In fact that's what my pending PR
does for MongoDB. Right now it even
allows to work with different value column names for the same table (either in the same or
in different documents/records) but I plan to add a check disallowing this for the sake of
portability to stores with a fixed schema.
I don’t follow that one. A fixed schema would be fine here, just with two columns instead
of one, no?
2014-06-20 13:00 GMT+02:00 Emmanuel Bernard <emmanuel(a)hibernate.org>:
On 19 Jun 2014, at 14:54, Gunnar Morling <gunnar(a)hibernate.org> wrote:
>> valueColumnName is something that I elected no to use because NoSQL we bind to so
far do not have a strong schema. And at at given segmentColumnValue only correspond a
single value. It would come and bite me if someone for the same segment value had two
different value column names to differentiate two different sequence.
>> Would it really bite you? I think e.g. MongoDB could perfectly handle this case
via two different fields for the two sequences in the same document/segment.
> The two definitions share the same options except for valueColumnName.
> The table is roughly as followed
> key | value1 | value2
> 1 | 10 | 24
> What would be the MongoDB representation in your approach?
> It would look like this:
> "_id" : 1,
> "value1" : 10,
> "value2" : 24
> So you would get the different sequence values from different fields of that same
document. But I wouldn't recommend to do so due to the potential contention on that
single record. Thus I'd raise at least a warning during bootstrap. As it's not
portable to stores with a fixed schema, I'd rather not support it at all, though, and
raise an error.
Exactly. But that’s the thing, AFAIK we do *not* store it that way today as we don’t use
valueColumnName. So today we store it like this
so 10 and 24 has to both live at the same time in sequence _value.