perl DBI连接oracle的问题

对于不同的ORACLE连接串，可能需要调整连接方式,都需要有ORACLE客户端：

1. dwapprac =
     (DESCRIPTION =
     (ADDRESS = (PROTOCOL = TCP)(HOST = 10.125.60.25)(PORT = 1521))
     (ADDRESS = (PROTOCOL = TCP)(HOST = 10.125.60.26)(PORT = 1521))
     (LOAD_BALANCE = yes)
     (CONNECT_DATA =
       (SERVER = DEDICATED)
       (SERVICE_NAME = dwapprac)
       (FAILOVER_MODE =
         (TYPE = SELECT)
         (METHOD = BASIC)
         (RETRIES = 180)
         (DELAY = 5)
       )
     )
   )

my $db_url="dbi:Oracle:$database_name";
                my $dbh = DBI->connect($db_url,$db_user,$db_password
                                ,{AutoCommit => 1
                                ,RaiseError => 0
                                ,PrintError => 0}
                               ) or printf STDERR "$DBI::err ($DBI::errstr)\n";
                unless ( defined($dbh) ) { return undef; }
                return ($db_type,$dbh);

2. dwapp =
  (DESCRIPTION =
    (LOAD_BALANCE=NO)
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 10.125.70.54)(PORT = 1522))
      (ADDRESS = (PROTOCOL = TCP)(HOST = 10.125.70.55)(PORT = 1522))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = dwapp)
    )
  )

my $db_url="dbi:Oracle:host=$host;sid=$database_name;port=$port";
                my $dbh = DBI->connect($db_url,$db_user,$db_password
                                ,{AutoCommit => 1
                                ,RaiseError => 0
                                ,PrintError => 0}
                               ) or printf STDERR "$DBI::err ($DBI::errstr)\n";
                unless ( defined($dbh) ) { return undef; }
                return ($db_type,$dbh);