try
              {
                  string connStr = "Provider=OraOLEDB.Oracle.1;User ID=scott;Password=tiger;Data Source=//localhost:1521/orcl;OLEDB.NET=1;PLSQLRSet=1;";
                  conn = new OleDbConnection(connStr);
                  conn.Open();

                  OleDbCommand cmd = new OleDbCommand();
                  cmd.Connection = conn;

                  OleDbParameter param = cmd.CreateParameter();
                  param.ParameterName = "O_ENAME";
                  param.Direction = ParameterDirection.Output;
                  param.OleDbType = OleDbType.Char;
                  param.Size = 15;

                  cmd.Parameters.Clear();
                  cmd.Parameters.Add(param);

                  cmd.CommandType = CommandType.Text;
                  cmd.CommandText = "{CALL SCOTT.EMPINFO(?)}";

                  OleDbDataReader reader = cmd.ExecuteReader();
                  DataTable dt = reader.GetSchemaTable();
              }

CREATE OR REPLACE PROCEDURE
EMPINFO(O_ENAME OUT VARCHAR2)
IS
BEGIN
SELECT ENAME
INTO O_ENAME
FROM EMP
WHERE EMPNO=7369;
END;
/