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From Mark Thornton <mthorn...@optrak.co.uk>
Subject float precision
Date Wed, 15 Aug 2007 14:42:36 GMT
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


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