[DERBY-853] ResultSetMetaData.getScale returns inconsistent values for DOUBLE type.

• Type: Bug
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 10.2.1.6
• Fix Version/s: 10.13.1.0
• Component/s: JDBC
• Labels: derby_triage10_5_2
• Urgency: Normal
• Issue & fix info: Newcomer, Repro attached
• Assignee: Danoja Dias
• Reporter: Daniel John Debrunner
• Created: 21/Jan/06 04:28
• Updated: 04/Aug/16 02:26
• Resolved: 04/Aug/16 02:26

Description

If a DOUBLE column is returned in the result set then getScale() returns 0.
If a DOUBLE expression is returned and the expression is the result of a DOUBLE combined with a DECIMAL then it seems the scale from the decimal sometimes affects the result set metadata.

E.g. DECIMAL(10,2) - DOUBLE returns a DOUBLE with getScale() returning 2.

See the test output for jdbcapi/metadata.java

double – precision: 15 scale: 0 display size: 22 type name: DOUBLE
double precision - dec(10,2) – precision: 15 scale: 0 display size: 22 type name: DOUBLE
dec(10,2) - double precision – precision: 15 scale: 2 display size: 22 type name: DOUBLE

First line is a DOUBLE column, second is DOUBLE - DECIMAL, third is DECIMAL - DOUBLE

I assume the scale should always be zero for a DOUBLE, as it holds no meaning, but I can't see any proof of that in JDBC spec, javadoc or tutorial book.

Issue Links

• is depended upon by: DERBY-6870 Google Summer of Code 2016: Derby bug fixing