You are viewing a plain text version of this content. The canonical link for it is here.

Posted to derby-user@db.apache.org by Mark Thornton <mt...@optrak.co.uk> on 2007/08/15 16:42:36 UTC

float precision

Derby 10.2.1.7 rejects a data type of "FLOAT(53)" despite the 
documentation including:

"The default precision for FLOAT is 53 and is equivalent to DOUBLE 
PRECISION"

The error given is
java.sql.SQLSyntaxErrorException: Value '53' is not a valid precision 
for FLOAT

Although an 8 byte IEEE floating point value has 52 explicit mantissa 
bits, there is also an implicit 1 bit, so 53 is the correct precision 
(at least that is my understanding) for normal values.

http://issues.apache.org/jira/browse/DERBY-2287
suggests that someone thinks 52 is right answer.

Mark Thornton