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From "Andrew McRae (JIRA)" <j...@apache.org>
Subject [jira] Created: (DERBY-4251) Derby EmbedResultSet does not conform to JDBC API for getRow()
Date Mon, 01 Jun 2009 10:24:07 GMT
Derby EmbedResultSet does not conform to JDBC API for getRow()
--------------------------------------------------------------

                 Key: DERBY-4251
                 URL: https://issues.apache.org/jira/browse/DERBY-4251
             Project: Derby
          Issue Type: Bug
          Components: JDBC
    Affects Versions: 10.5.1.1, 10.4.2.0
         Environment: Windows XP, and Java 6 or Java 1.4.2
            Reporter: Andrew McRae


According to source of the Derby version I first found it in, and the version just released
today, here is the offending code:

https://svn.apache.org/repos/asf/db/derby/code/tags/10.5.1.1/java/engine/org/apache/derby/impl/jdbc/EmbedResultSet.java
{quote}
{{
	public int getRow() throws SQLException {
		// getRow() is only allowed on scroll cursors
		checkScrollCursor("getRow()");

		/*
		 * * We probably needn't bother getting the text of * the underlying
		 * statement but it is better to be * consistent and we aren't
		 * particularly worried * about performance of getRow().
		 */
		return theResults.getRowNumber();
	}
}}
{quote}

The comment and the check for scrollability is incorrect. The Javadoc comment for this getRow
is a duplicate of the Sun JDK API for ResultSet.getRow(), and if the author had just written
it according to their own javadoc there would be no problem. 
See spec here:
 http://java.sun.com/j2se/1.3/docs/api/java/sql/ResultSet.html#getRow()

The Sun Javadoc does not spell out any exceptions to the required behaviour. getRow should
always work regardless of whether the result set is scrollable because the issue of scrollability
is whether the client can *reposition* the cursor to change the current row of the result
set. Simply *reading* the current row number is different and unrelated to changing the current
row number. 
Therefore getRow() should work for FORWARD_ONLY ResultSets, but Derby currently fails on this.

I haven't looked at what " theResults.getRowNumber() " does, but I hope the fix for this bug
is as simple as removing the call to checkScrollCursor;


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