On 19 Jun 2014, at 14:54, Gunnar Morling <gun...@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.
>
> @TableGenerator(
> name=“1”,
> table=“Seq_table”,
> pkColumnName=“key”,
> pkColumnValue=“1”,
> valueColumnName=“value1”
> )
> @TableGenerator(
> name=“2”,
> table=“Seq_table”,
> pkColumnName=“key”,
> pkColumnValue=“1”,
> valueColumnName=“value2”
> )
>
> The two definitions share the same options except for valueColumnName.
> The table is roughly as followed
>
> TABLE(Seq_table)
> 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
{
“_id”: 1,
“sequence_value”: 10
}
so 10 and 24 has to both live at the same time in sequence _value.
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