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https://issues.apache.org/jira/browse/DERBY-3097?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12601421#action_12601421
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Knut Anders Hatlen commented on DERBY-3097:
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Not all that useful, but in case someone finds it interesting...
I tried to modify the test case so that it would run on Derby. To get the
correct syntax, I did
a) replace getCurrentConnection() with
DriverManager.getConnection("jdbc:default:connection") in the Java method
b) add a CREATE FUNCTION statement to create the NEST_THIS function
c) change "create unique btree index" to "create unique index"
d) change "properties index=null" to "--DERBY-PROPERTIES index=null"
The first problem that I ran into, was that the optimizer override caused a
syntax error. Apparently, optimizer overrides are not supported for DELETE
statements. Not sure if this is a bug or not. The documentation says that they
work on FROM clauses, and I couldn't find anything about their being limited to
SELECT FROM. Anyway, it was pretty easy to enable it in the parser (can't
guarantee that it works perfectly, though). Just change a flag from false to
true in sqlgrammar.deleteBody().
Next problem was that functions don't allow SQL statements that modify data.
Since the test case indicates that it was supported in Cloudscape, it might be
that only a simple change in the parser is required, so that it accepts
"MODIFIES SQL" in CREATE FUNCTION statements, but I didn't get that far before
I ran out of daylight.
> Unnecessary if statement can be removed from BaseActivation.getColumnFromNow
> ----------------------------------------------------------------------------
>
> Key: DERBY-3097
> URL: https://issues.apache.org/jira/browse/DERBY-3097
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 10.4.1.3
> Reporter: Bryan Pendleton
> Assignee: Bryan Pendleton
> Priority: Minor
> Attachments: checkNumOpens.diff
>
>
> In BaseActivation.java there is the following code:
> protected final DataValueDescriptor getColumnFromRow(int rsNumber, int colId)
> throws StandardException {
> if( row[rsNumber] == null)
> {
> /* This actually happens. NoPutResultSetImpl.clearOrderableCache
> attempts to prefetch invariant values
> * into a cache. This fails in some deeply nested joins. See
> Beetle 4736 and 4880.
> */
> return null;
> }
> return row[rsNumber].getColumn(colId);
> }
> During the investigation of DERBY-3033, I came to the conclusion that this
> "if" statement is no longer necessary, and in fact is counter-productive, for
> it makes diagnosing other problems harder by delaying the point at which data
> structure problems are exposed as errors in the code.
> This JIRA issue requests that this code be evaluated, to determine whether or
> not it truly is necessary, and, if it is not necessary, suggests that it
> should be removed, to result in simpler, clearer code.
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