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https://issues.apache.org/jira/browse/DERBY-2550?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12489050
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Knut Anders Hatlen commented on DERBY-2550:
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Hi Christian,
This Spring issue has been discussed earlier. See this thread:
http://mail-archives.apache.org/mod_mbox/db-derby-user/200607.mbox/[EMAIL
PROTECTED]
Note that Types.NULL identifies an SQL value (NULL), not an SQL type
(http://java.sun.com/javase/6/docs/api/java/sql/Types.html#NULL).
> Types.NULL is not accepted when using setNull on a PreparedStatment
> -------------------------------------------------------------------
>
> Key: DERBY-2550
> URL: https://issues.apache.org/jira/browse/DERBY-2550
> Project: Derby
> Issue Type: Bug
> Components: JDBC
> Affects Versions: 10.2.2.0
> Environment: Ubuntu 6.10, Java 5 and Mac OSX 10.4, Java5
> Spring 2.x
> Derby "Embedded" mode
> Reporter: Christian Schwanke
> Attachments: SimpleEmbeddedTestCase.java
>
>
> Inserting data into table using a PreparedStatement will fail, if the
> setNull() method is used with Types.NULL.
> I have tracked down the problem to the method "isJDBCTypeEquivalent(int
> existingType, int jdbcTypeId)" in class
> "org.apache.derby.iapi.types.DataTypeDescriptor" (Line 922).
> This method checks the current column type against the type specified by the
> application. The setNull() method will throw an error, if the types do not
> match. The problem here is, that isJDBCTypeEquivalent will not accept
> Types.NULL as an valid equivalent to the column type.
> When writing the JDBC code by hand one can avoid the problem - but this is
> quite annoying since the Jdbc-Support provided by the Spring-Framework will
> use setNull() with Types.NULL making it impossible to use Derby with Spring's
> plain JdbcTemplate.
> Example:
> String preparedSql = "INSERT INTO demo (stringValue) VALUES (?)";
> PreparedStatement pstmt = con.prepareStatement(preparedSql);
> // this will work, since the given type is equivalent
> pstmt.setString(1, null);
> pstmt.execute();
> // this will fail, since Types.NULL is not recognized as equivalent
> pstmt.setNull(1, Types.NULL);
> pstmt.execute();
> The exception thrown is
> "java.sql.SQLException: An attempt was made to get a data value of type
> 'VARCHAR' from a data value of type '0'"
> As far as I can see, it is sufficient to modify the first part of the
> isJDBCTypeEquivalent-method. At least, it solved my problems.
> Current:
> // Any type matches itself.
> if (existingType == jdbcTypeId)
> return true;
> Fix:
> // Any type matches itself.
> if (existingType == jdbcTypeId || jdbcTypeId == Types.NULL)
> return true;
> I've attached a simple TestCase to reproduce the problem.
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