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https://issues.apache.org/jira/browse/DERBY-3181?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15299241#comment-15299241
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ASF subversion and git services commented on DERBY-3181:
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Commit 1745414 from [~bryanpendleton] in branch 'code/trunk'
[ https://svn.apache.org/r1745414 ]
DERBY-3181: DatabaseMetaData.getBestRowIdentifier behavior with invalid scope
This patch was contributed by Danoja Dias (danojadias at gmail dot com)
The DatabaseMetaData.getBestRowIdentifier method takes a number of arguments,
including "scope", which is supposed to be one of the enumerated values:
bestRowTemporary, bestRowTransaction, and bestRowSession.
If an invalid scope argument was passed to this method, Derby was returning
a hard-coded "empty" row identifier, which was slightly different, in detail,
to the row identifier that is returned for a valid scope argument.
Since JDBC does not require that we return such a row identifier for an
invalid scope argument, it seems cleaner and more useful to throw an
exception with a message indicating that an invalid scope argument was
passed. The caller can then correct their application to make the call with
a valid scope argument, and will then receive a valid row identifier.
> isNullable on ResultSetMetaData from DatabaseMetaData.getBestRowIdentifier
> values are opposite when there is no rows in ResultSet vs. when there is a
> row.
> ----------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-3181
> URL: https://issues.apache.org/jira/browse/DERBY-3181
> Project: Derby
> Issue Type: Bug
> Components: JDBC
> Affects Versions: 10.4.1.3
> Reporter: Myrna van Lunteren
> Assignee: Danoja Dias
> Priority: Trivial
> Labels: derby_triage10_5_2
> Attachments: Derby-3181.diff, Derby3181.diff, repro.java,
> testChange.diff
>
>
> With code like the following:
> DatabaseMetaData dmd = conn.getMetaData();
> ResultSet rs = dmd.getBestRowIdentifier(null,"APP","a",3,true);
> ResultSetMetaData rsmd = rs.getMetaData();
> int actualCols = rsmd.getColumnCount();
> for (int i = 0; i < actualCols; i++)
> {
> System.out.print("getColumnName: " + rsmd.getColumnName(i+1)
> + ", isNullable: ");
> System.out.println(rsmd.isNullable(i+1));
> }
> The printed values for isNullable returned are opposite of what they are when
> the getBestRowIdentifier call looks like this:
> ResultSet rs = dmd.getBestRowIdentifier(null,"APP","a",1,true);
> In the latter case, the values are:
> getColumnName: SCOPE, isNullable: 0
> getColumnName: COLUMN_NAME, isNullable: 1
> getColumnName: DATA_TYPE, isNullable: 0
> getColumnName: TYPE_NAME, isNullable: 1
> getColumnName: COLUMN_SIZE, isNullable: 0
> getColumnName: BUFFER_LENGTH, isNullable: 0
> getColumnName: DECIMAL_DIGITS, isNullable: 0
> getColumnName: PSEUDO_COLUMN, isNullable: 0
> In the first case, the values are:
> getColumnName: SCOPE, isNullable: 1
> getColumnName: COLUMN_NAME, isNullable: 0
> getColumnName: DATA_TYPE, isNullable: 1
> getColumnName: TYPE_NAME, isNullable: 1
> getColumnName: COLUMN_SIZE, isNullable: 1
> getColumnName: BUFFER_LENGTH, isNullable: 1
> getColumnName: DECIMAL_DIGITS, isNullable: 1
> getColumnName: PSEUDO_COLUMN, isNullable: 1
> The isNullable value should be stable.
> It's probably worthwhile verifying what the value *should* be in the first
> place.
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