False, as it depends on the application of affinity. If you are storing the
floating point value in a column that does not have an affinity (ie, no
conversions are performed), then it is stored exactly (except for NaN).
Application of affinity (ie, real) will cause the -0.0 to be stored as the
integer 0 and thus the sign will be lost on retrieval (as well as the
conversion of NaN to NULL).
>>> import apsw
>>> import math
>>> db = apsw.Connection('')
>>> db.execute('create table x(x)');
>>> db.execute('insert into x values (?)', (math.nan,))
>>> db.execute('insert into x values (?)', (math.inf,))
>>> db.execute('insert into x values (?)', (-math.inf,))
>>> db.execute('insert into x values (?)', (0.0,))
>>> db.execute('insert into x values (?)', (-0.0,))
>>> for row in db.execute('select x from x'): print row
...
Row(x=None)
Row(x=inf)
Row(x=-inf)
Row(x=0.0)
Row(x=-0.0)
>>> db.execute('drop table x');
>>> db.execute('create table x(x real)');
>>> db.execute('insert into x values (?)', (math.nan,))
>>> db.execute('insert into x values (?)', (math.inf,))
>>> db.execute('insert into x values (?)', (-math.inf,))
>>> db.execute('insert into x values (?)', (0.0,))
>>> db.execute('insert into x values (?)', (-0.0,))
>>> for row in db.execute('select x from x'): print row
...
Row(x=None)
Row(x=inf)
Row(x=-inf)
Row(x=0.0)
Row(x=0.0)
--
The fact that there's a Highway to Hell but only a Stairway to Heaven says a
lot about anticipated traffic volume.
>-----Original Message-----
>From: sqlite-users [mailto:sqlite-users-
>boun...@mailinglists.sqlite.org] On Behalf Of Donald Shepherd
>Sent: Wednesday, 31 July, 2019 16:50
>To: SQLite mailing list
>Subject: Re: [sqlite] Floating point literals
>
>That's not correct, verified several times by my own testing and
>re-verified on the recent discussion about -0.0 on this mailing list.
>
>If you store -0.0 as a double, it will be stored as an integer as a
>space-saving mechanism. That integer is 0. When you retrieve the
>value as
>a double it will be 0.0. The sign has been stripped.
>
>Regards,
>Donald Shepherd.
>
>On Thu, 1 Aug 2019 at 08:47, Keith Medcalf <kmedc...@dessus.com>
>wrote:
>
>>
>> The -0.0 is only for conversion to text. Otherwise -0.0 is
>preserved both
>> on input and output (including input text conversions). It is only
>the
>> conversion of -0.0 TO text that drops the sign. NaN becomes a NULL
>(ie, a
>> double is not stored, a NULL value is stored). Everything else is
>> preserved including Inf and -Inf.
>>
>> --
>> The fact that there's a Highway to Hell but only a Stairway to
>Heaven says
>> a lot about anticipated traffic volume.
>>
>>
>> >-----Original Message-----
>> >From: sqlite-users [mailto:sqlite-users-
>> >boun...@mailinglists.sqlite.org] On Behalf Of Igor Tandetnik
>> >Sent: Wednesday, 31 July, 2019 15:34
>> >To: sqlite-users@mailinglists.sqlite.org
>> >Subject: Re: [sqlite] Floating point literals
>> >
>> >On 7/31/2019 5:15 PM, Eric Reischer wrote:
>> >> I understand you can *retrieve* a non-quantized value using
>> >sqlite3_column_double(), but I don't see a way to set one without
>> >having to printf() the floating point value.
>> >
>> >sqlite3_bind_double
>> >
>> >> Can this be done using sqlite3_bind_* interfaces, or do they
>> >quantize as well?
>> >
>> >Yes. No; except that I seem to recall it mentioned that NaN is
>> >treated as SQL NULL, and negative zero is normalized to positive
>> >zero.
>> >
>> >> The goal is to copy the straight 8-byte (or precision-extended
>4-
>> >byte) IEEE value into the column into the database (where the
>column
>> >is defined as a FLOAT) without having to build a SQL statement
>that
>> >has an obscene number of digits in each floating point field.
>> >
>> >That's precisely what bound parameters and sqlite3_bind_X
>functions
>> >are for.
>> >--
>> >Igor Tandetnik
>> >
>> >
>> >_______________________________________________
>> >sqlite-users mailing list
>> >sqlite-users@mailinglists.sqlite.org
>> >http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-
>users
>>
>>
>>
>> _______________________________________________
>> sqlite-users mailing list
>> sqlite-users@mailinglists.sqlite.org
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>users
>>
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