sjoerd at monetdb.org
Wed Oct 21 15:50:13 CEST 2015
On 21/10/15 15:41, Dimitar Nedev wrote:
> Thanks for sending it, Stefan. Indeed, the page was quite helpful. That's how I fixed some real/float/double issues earlier.
> I see, so if I've got a boolean column, calling
> where 'b' is a BAT would not sufficient to identify it as a boolean? It will return TYPE_bte (2).
The name ATOMstorage should tell you a lot: it's about *storage*, not
semantics. A bit uses the same amount of storage as a bte, but that
doesn't mean those bytes are interpreted the same. It may well be that
you shouldn't use ATOMstorage here.
> OK, I'll need to push the logic a bit further.
>> On 2015-Oct-21, at 15:14, Stefan Manegold <Stefan.Manegold at cwi.nl> wrote:
>> our MAL representation of SQL type BOOLEAN is MAL type :bit,
>> and the C representation of MAL type :bit is (out) C type bit,
>> which is indeed 1 byte (8 bit) wide, because we need to accommodate 3 values:
>> TRUE, FALSE & NULL (NIL).
>> Thus, BOOLEAN columns are (should be) represented by a BAT with tail type (:)bit,
>> which is (semantically) not the same as type TINYINT / (:)bte.
>> ----- On Oct 21, 2015, at 3:07 PM, Dimitar Nedev dimitar.nedev at monetdbsolutions.com wrote:
>>> Hey guys,
>>> A boolean type column seems to fit in a byte, I guess the extra space is to
>>> represent nulls (since it ain't a qubit). But does that mean that no column
>>> type is actually ':bit'?
>>> Given a BAT, how to distinguish between a byte (tinyint) column and a boolean
>>> developers-list mailing list
>>> developers-list at monetdb.org
>> | Stefan.Manegold at CWI.nl | DB Architectures (DA) |
>> | www.CWI.nl/~manegold/ | Science Park 123 (L321) |
>> | +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
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