Continuing into the SQL 2003 foundation spec[3] I can't find any
explicit mention of NaN/INFINITE numbers for either FLOAT, REAL or
DOUBLE PRECISION sql datatypes.
The combined information from
- chapter 4.4.1 "Characteristics of numbers", and
- chapter 6.1 "Data Types", section "Syntax Rules", paragraphs 24)
through 27),
state that the maximum and minimum numbers supported are implementation
defined for the sql datatypes REAL, FLOAT and DOUBLE PRECISION.
So, yes, it boils down to what the database acutally supports, and at
the moment Derby does not support neither NaN or INFINITE.
Given that Derby is a 100% java database it would seem appropriate that
the legal java numbers NaN and INFINITE should be supported for the java
types Double and Float.
Cheers,
Thomas
[3] ISO/IEC 9075-2:2003 (E), "Information technology - database
languages - SQL - Part 2: Foundation (SQL/Foundation)"
Thomas Nielsen wrote:
Neither the JDBC 4.0 specification[1] nor "JDBC API Tutorial and
Reference"[2] mention handling of the NaN or INFINITE numbers at all
AFAICT.
As there is no mention of how to handle *jdbc* doubles (and literals),
it seems this then boils down to how/if the database handle the *sql*
double (and literals).
Cheers,
Thomas
[1] JSR-221, JDBC 4.0,
http://jcp.org/aboutJava/communityprocess/final/jsr221/index.html
[2] "JDBC API Tutorial and Reference, Third Edt.", Fisher, Ellis &
Bruce, Addison-Wesley 2003.
Andrew ``Bass'' Shcheglov wrote:
On Dec 19, 2007 12:23 PM, Thomas Nielsen <[EMAIL PROTECTED]> wrote:
Looking at the derby code on the main trunk, I see the exception is
intentional, as there is an explicit check for NaN values in
NumberDataType.normalizeDOUBLE().
Not sure if this is another DB2 compatability issue/limitation or not.
Maybe someone with deeper knowledge can give more details on this?
This is odd,
for Oracle, for instance, fully supports IEEE 754 (since 10g):
http://www.oracle.com/technology/sample_code/tutorials/jdbc10g/ieeedatatypes/files/IEEEDatatypes.pdf
http://download.oracle.com/docs/cd/B14117_01/server.101/b10759/sql_elements003.htm
--
Thomas Nielsen
