Major Description
I have a table created in the Derby database with a field as "float". I am able to successfully insert into this field the value FLOAT.MAX_VALUE (3.4028235E38). But when I try to query this field and try to use resultSet.getFloat() to retrieve this value I get a SQLException thrown.
The derby driver that I am using is the one that is part of our Glassfish 9.0 build.
The stack trace is :
org.apache.derby.client.am.LossOfPrecisionConversionException: Invalid data conversion:Requested conversion would result in a loss of precision of 3.4028235E38
at org.apache.derby.client.am.CrossConverters.getFloatFromDouble(Unknown Source)
at org.apache.derby.client.am.Cursor.getFloat(Unknown Source)
at org.apache.derby.client.am.ResultSet.getFloat(Unknown Source)
at DerbyFloat.testFloat(DerbyFloat.java:121)
at DerbyFloat.main(DerbyFloat.java:139)
I have attached a simple java program that I have used to reproduce this problem.
import java.sql.*;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
public class DerbyFloat {
/* Derby */
static final String userName = "APP";
static final String password = "APP";
static final String connectionURL =
"jdbc:derby://localhost:1527/sun-appserv-samples;retrieveMessagesFromServerOnGetMessage=true;";
static final String driverName = "org.apache.derby.jdbc.ClientDriver";
Connection conn;
public DerbyFloat() {}
void init() throws SQLException
{ conn = getConnection(driverName, connectionURL, userName, password); } private static Connection getConnection(String driverName, String connectionURL,
String userName, String password) throws SQLException {
Connection conn = null;
try
{ Class.forName (driverName); }catch (ClassNotFoundException e)
{ System.out.println("Could not load the driver class. Error is " + e); }try
{ conn = DriverManager.getConnection(connectionURL, userName, password); conn.setAutoCommit(false); } catch (SQLException e) {
System.out.println("Error while getting connection");
SQLException currentException = e;
do
while (currentException != null);
throw e;
}
return conn;
}
public void insertRows() throws java.sql.SQLException {
PreparedStatement ps;
try
catch (SQLException e)
{ System.out.println("Table does not exist"); }
ps = conn.prepareStatement("CREATE TABLE DERBYFLOAT (ID INT PRIMARY KEY, FLOATDATA FLOAT)");
// ps = conn.prepareStatement("CREATE TABLE DERBYFLOAT (ID INT PRIMARY KEY, FLOATDATA FLOAT(24))");
ps.executeUpdate();
ps = conn.prepareStatement("DELETE FROM DERBYFLOAT");
ps.executeUpdate();
ps = conn.prepareStatement(
"INSERT INTO DERBYFLOAT(ID, FLOATDATA) VALUES(1, 1)");
ps.executeUpdate();
ps = conn.prepareStatement(
"INSERT INTO DERBYFLOAT(ID, FLOATDATA) VALUES(2, 124567890123456)");
ps.executeUpdate();
ps = conn.prepareStatement(
"INSERT INTO DERBYFLOAT(ID, FLOATDATA) VALUES(3, 3.4028235E37)");
ps.executeUpdate();
ps = conn.prepareStatement(
"INSERT INTO DERBYFLOAT(ID, FLOATDATA) VALUES(4, 3.4028235E38)");
ps.executeUpdate();
}
public void testFloat() throws java.sql.SQLException {
PreparedStatement ps = conn.prepareStatement(
"SELECT ID, FLOATDATA FROM DERBYFLOAT");
ResultSet rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
while(rs.next()) {
/*
Object o = rs.getObject
;
String columnTypeName = rsmd.getColumnTypeName;
System.out.println("column " + + " type: " + columnTypeName +
" (" + rsmd.getColumnType + ") " + "\t\tJava Type: " + o.getClass());
*/
System.out.println("\n Value of field 1 uing getInt() : " + rs.getInt(1));
try
catch (SQLException e)
{ System.out.println("\n Value of field 2 using getFloat() resulted in a SQLException"); e.printStackTrace(); System.out.println("\n Value of field 2 using getObject() : " + rs.getObject(2)); }}
}
public static final void main (String args [])
{
DerbyFloat dbFloat = new DerbyFloat();
try
catch (SQLException ex)
{ System.out.println("SQLException : "+ ex); ex.printStackTrace(); }}
}