On 7/7/16 1:40 AM, Dinesh Bajaj wrote:
Hello Rick,
Many thanks for your response.
I can surely share the Java Code of the UDF. Here is the code:
//************** START OF FUNCTION CODE *****************************
public static BigDecimal getInvoiceTotal(int invoiceNumber)
throws SQLException {
Connection connection =
DriverManager.getConnection("jdbc:default:connection");
BigDecimal invoiceTotal = getItemsTotal(connection,
invoiceNumber);
String sql = "SELECT discount, additionalcharge FROM invoices "
+ "WHERE id = " + invoiceNumber;
try (Statement statement = connection.createStatement()) {
try (ResultSet result = statement.executeQuery(sql)) {
if (result.next()) {
BigDecimal amount = result.getBigDecimal(1);
//discount
if (!result.wasNull()) {
invoiceTotal = invoiceTotal.subtract(amount);
}
amount = result.getBigDecimal(2); // additional charge
if (!result.wasNull()) {
invoiceTotal = invoiceTotal.add(amount);
}
}
}
}
return invoiceTotal;
}
private static BigDecimal getItemsTotal(Connection connection,
int invoiceNumber) throws SQLException {
String sql = "SELECT rate * quantity FROM invoice_items WHERE "
+ "invoice_id = " + invoiceNumber;
BigDecimal total = BigDecimal.ZERO;
try (Statement statement = connection.createStatement()) {
try (ResultSet result = statement.executeQuery(sql)) {
BigDecimal amount = null;
while (result.next()) {
amount = result.getBigDecimal(1).setScale(2,
RoundingMode.HALF_UP);
total = total.add(amount);
}
}
}
return total;
}
//**************END OF FUNCTION CODE *****************************
Should you require any other info, kindly let me know.
Thanks,
Dinesh
On Thursday, 7 July 2016 7:34 AM, Rick Hillegas
<[email protected]> wrote:
On 7/5/16 9:11 PM, Dinesh Bajaj wrote:
> CREATE FUNCTION invoice_total
> ( invoiceNumber int )
> RETURNS DECIMAL
> LANGUAGE JAVA
> PARAMETER STYLE JAVA
> READS SQL DATA
> EXTERNAL NAME 'FXBilling.DBJAR.DBMethods.getInvoiceTotal'
Hi Dinesh,
It's hard to say what's going on. Could you share the Java code which
implements getInvoiceTotal()? The following code works for me (I changed
your function declaration to return a DECIMAL with a non-zero scale).
Here is my version of the function...
public class SampleUDF
{
public static BigDecimal getInvoiceTotal(int invoiceNumber)
throws SQLException
{
Connection conn =
DriverManager.getConnection("jdbc:default:connection");
try (PreparedStatement ps = conn.prepareStatement("select total
from invoices where invoiceNumber = ?"))
{
ps.setInt(1, invoiceNumber);
try (ResultSet rs = ps.executeQuery())
{
if (rs.next())
{
return rs.getBigDecimal(1);
}
else { return null; }
}
}
}
}
...and here is a script which invokes it...
connect 'jdbc:derby:memory:db;create=true';
create table invoices(invoiceNumber int primary key, total decimal(10,2));
insert into invoices values (1, 100.30), (2, 200.60);
CREATE FUNCTION invoice_total
( invoiceNumber int )
RETURNS DECIMAL(10,2)
LANGUAGE JAVA
PARAMETER STYLE JAVA
READS SQL DATA
EXTERNAL NAME 'SampleUDF.getInvoiceTotal';
values invoice_total(1);
Hope this helps,
-Rick
Hi Dinesh,
I'm afraid that I can't explain your results from the evidence you have
provided. I successfully compiled the invoice_total() function. It
executed correctly when I declared the function with the READS SQL DATA
clause. However, when I changed that clause to be NO SQL, then I saw the
error which you are seeing: "The external routine is not allowed to
execute SQL statements."
Could you provide some additional information:
1) What version of Derby are you using?
2) What does dblook produce as the DDL for invoice_total()? You can run
dblook as follows:
java org.apache.derby.tools.dblook -d $connectionURL
where $connectionURL is your connection string, e.g., "jdbc:derby:db"
Thanks,
-Rick
