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https://issues.apache.org/jira/browse/DERBY-5525?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13165320#comment-13165320
]
Knut Anders Hatlen commented on DERBY-5525:
-------------------------------------------
For the string literal case, I thought maybe constant folding might do the
trick, so I added this method to SimpleStringOperatorNode:
ValueNode evaluateConstantExpressions() throws StandardException {
if (operand instanceof CharConstantNode) {
CharConstantNode node = (CharConstantNode) operand;
StringDataValue val = (StringDataValue) node.getValue();
if (methodName.equals("upper")) {
val = val.upper(null);
} else {
val = val.lower(null);
}
return (ValueNode) getNodeFactory().getNode(
C_NodeTypes.CHAR_CONSTANT_NODE,
val.getString(),
getContextManager());
}
return this;
}
However, the meta-data seems to have been calculated before we do constant
folding, so the precision is still wrong:
ij> values upper('Straße');
1
------
STRAS&
1 row selected
However, the constant folding appears to be an improvement, since wrapping
calling LENGTH on the result from UPPER changed from
ij> values length(upper('Straße'));
1
-----------
6
1 row selected
to
ij> values length(upper('Straße'));
1
-----------
7
1 row selected
> Precision for UPPER function is wrong if the returned value is longer than
> the literal argument
> -----------------------------------------------------------------------------------------------
>
> Key: DERBY-5525
> URL: https://issues.apache.org/jira/browse/DERBY-5525
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.8.2.2
> Reporter: Knut Anders Hatlen
>
> Seen in ij in a database with territory based collation and German locale:
> ==vv= COPIED FROM IJ CONSOLE =vv==
> ij> VALUES UCASE('Straßenbahn');
> 1
> -----------
> STRASSENBA&
> 1 Zeile ausgewählt
> ==================================
> And with JDBC calls:
> Connection c = DriverManager.getConnection(
> "jdbc:derby:memory:db;create=true;territory=de_DE;" +
> "collation=TERRITORY_BASED");
> Statement s = c.createStatement();
> ResultSet rs = s.executeQuery("values upper('Straße')");
> System.out.println(rs.getMetaData().getPrecision(1));
> rs.next();
> System.out.println(rs.getString(1));
> This prints
> 6
> STRASSE
> The precision is wrong, since the returned value is 7 characters long.
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