Getting a Clob Value from an OUT Parameter

Question

I am having trouble fetching the CLOB Value(an XML Document) from an Out parameter. I have been
trying to fetch the value into a String, an OracleClob, etc.. no luck still get either an invalid
cast or a DBNULL value. Is there an example out there for returning and manipulating CLOBS in either VB.NET or in C#.
Thanks,
Scott E. Hunley

Answer 1

Scott,
Hopefully, this will help:
========================== C# code begin ===========================
using System;
using System.Data;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
namespace Test
class OutClob
static OracleCommand cmd;
static void Execute(string sql)
try
cmd.CommandText = sql;
cmd.ExecuteNonQuery();
catch (Exception e)
Console.WriteLine(e.Message);
static void Main(string[] args)
// connect
OracleConnection con = new OracleConnection();
con.ConnectionString = "user id=scott;password=tiger;data source=ora92;";
con.Open();
// instantiate the command object
cmd = new OracleCommand();
cmd.Connection = con;
// drop table
Execute("drop table foo");
// create table
Execute("create table foo (num number, xml clob)");
// insert a row with xml data in a CLOB column
Execute("insert into foo values (1, '<foo>bar</foo>')");
// bind and output parameter for an anonymous PL/SQL block
OracleParameter p1 = cmd.Parameters.Add("p1", OracleDbType.Clob);
p1.Direction = ParameterDirection.Output;
// execute the anonymous PL/SQL block which returns a CLOB as an
// output parameter of type OracleClob
Execute("begin select xml into :1 from foo where num = 1; end;");
// Obtain the clob with the proper cast
OracleClob clob = (OracleClob)p1.Value;
// print out the XML document
Console.WriteLine(clob.Value);
========================== C# code end ===========================
Output:
<foo>bar</foo>