If using a tnsnames.ora file to retrieve connection information and to prevent connection information conflicts, do not specify the following connection properties:

  • AlternateServers
  • EncryptionMethod
  • FailoverMode
  • LoadBalancing
  • ServerName
  • ServiceName
  • PortNumber
  • ServerType
  • SID

If any of these properties are specified in addition to the TNSNamesFile and TNSServerName properties, the driver throws an exception. For example, if the net service name entry ARMSTRONG.ACCT specifies the LOAD_BALANCE parameter as shown in the following example:

ARMSTRONG.ACCT =
  (DESCRIPTION = 
  (ADDRESS_LIST= 
     (FAILOVER = on)
     (LOAD_BALANCE = on) 
     (ADDRESS= (PROTOCOL = TCP)(HOST = server1)(PORT = 1521))
     (ADDRESS= (PROTOCOL = TCP)(HOST = server2)(PORT = 1521))
     (ADDRESS= (PROTOCOL = TCP)(HOST = server3)(PORT = 1521))
   )

and you specify the LoadBalancing property in the driver connection URL as shown in the following example, the driver throws an exception.

jdbc:datadirect:oracle:TNSNamesFile=c:\\oracle92\\NETWORK\\
ADMIN\\tnsnames.ora;TNSServerName=FITZGERALD.SALES;LoadBalancing=true

The following table lists the Oracle driver properties that correspond to tnsnames.ora connect descriptor parameters. To prevent connection information conflicts, do not specify the listed properties if you use a tnsnames.ora file.

Table 1. Oracle Driver Property Mappings to tnsnames.ora Connect Descriptor Parameters
Oracle Driver Property tnsnames.ora Attribute
AlternateServers = servers_list 
ADDRESS_LIST = servers_list
The ADDRESS_LIST parameter contains connection information for one or multiple servers, using the ADDRESS parameter to specify the primary and alternate servers. For example:
(ADDRESS_LIST= 
   (ADDRESS= (PROTOCOL = TCP)(HOST = server1)(PORT = 1521))
   (ADDRESS= (PROTOCOL = TCP)(HOST = server2)(PORT = 1521))
   (ADDRESS= (PROTOCOL = TCP)(HOST = server3)(PORT = 1521))
)
The first ADDRESS parameter specifies connection information for the primary server. The second and third ADDRESS parameter specifies connection information for alternate servers.

When multiple servers are specified by the ADDRESS_LIST parameter, connection failover is automatically enabled. If FAILOVER=off, connection failover is disabled. You also can explicitly specify connection failover using the FAILOVER parameter.
FailoverMode = {connect | extended | select} 
FAILOVER_MODE = {TYPE={none | session | select}
[BACKUP=value] [METHOD=basic | preconnect] [RETRIES=value]
[DELAY=value] }
The FAILOVER_MODE parameter is specified in the CONNECT_DATA section to provide failover instructions for the driver. The FAILOVER_MODE parameter requires the TYPE parameter, which specifies the type of failover to be used. Other parameters are optional.
(CONNECT_DATA=
      (SERVICE_NAME = acct.us.yourcompany.com)
      (FAILOVER_MODE = 
         (BACKUP=server2)
         (TYPE=select)
         (METHOD=preconnect)
         (RETRIES=20)
         (DELAY=3)
     )
The FAILOVER_MODE parameter can only be used to enable extended connection failover or select failover. When multiple servers are specified by the ADDRESS_LIST parameter, connection failover is automatically enabled. If FAILOVER=off, connection failover is disabled. You also can explicitly specify connection failover using the FAILOVER parameter.
LoadBalancing = {true | false} 
LOAD_BALANCE = {on | off}
If LOAD_BALANCE=on, enables client load balancing. For example:
(ADDRESS_LIST= 
   (LOAD_BALANCE=on)
   (ADDRESS= (PROTOCOL = TCP)(HOST = server1)(PORT = 1521))
   (ADDRESS= (PROTOCOL = TCP)(HOST = server2)(PORT = 1521))
   (ADDRESS= (PROTOCOL = TCP)(HOST = server3)(PORT = 1521))
)
If the LOAD_BALANCE parameter is unspecified or LOAD_BALANCE=off, client load balancing is disabled.
PortNumber = port 
PORT = port
The ADDRESS_LIST parameter contains connection information for one or multiple servers, using the ADDRESS parameter to specify the primary and alternate servers. The PORT parameter is used within the ADDRESS parameter to specify the port number for each server entry. For example: 
(ADDRESS_LIST= 
   (ADDRESS= (PROTOCOL = TCP)(HOST = server1)(PORT = 1521))
   ...)
A port of 1521, the default port number when installing an Oracle database, is specified for server1.
EncryptionMethod = {noEncryption | SSL} 
PROTOCOL={TCP | TCPS}
The ADDRESS_LIST parameter contains connection information for one or multiple servers, using the ADDRESS parameter to specify the primary and alternate servers. The PROTOCOL parameter is used within the ADDRESS parameter to specify the network protocol to be used. It also is used to specify whether data is encrypted and decrypted when transmitted over the network between the driver and the server. For example, the following entry specifies that the TCP/IP protocol will be used with no encryption: 
(ADDRESS_LIST= 
   (ADDRESS= (PROTOCOL = TCP)(HOST = server1)(PORT = 1521))
   ...
 )
A port of 1521, the default port number when installing an Oracle database, is specified for server1.The following entry specifies that the TCP/IP protocol will be used with SSL encryption: 
(ADDRESS_LIST= 
   (ADDRESS= (PROTOCOL = TCPS)(HOST = server1)(PORT = 2484))
   ...
 )
A port of 2484, the port number recommended by Oracle for SSL, is specified for server1.
Note: Truststore information must still be specified using either the TrustStore and TrustStorePassword properties or Java system properties. Optionally, you can specify the ValidateServerCertificate and HostNameInCertificate properties.
ServerName = server_name 
HOST = server_name
The ADDRESS_LIST parameter contains connection information for one or multiple servers, using the ADDRESS parameter to specify the primary and alternate servers. The HOST parameter is used within the ADDRESS parameter to specify the server name for each server entry. The server entry can be an IP address or a server name. For example: 
(ADDRESS_LIST= 
   (ADDRESS= (PROTOCOL = TCP)(HOST = server1)(PORT = 1521))
   ...
 )
The server name server1 is specified in the first server entry.
ServerType = {shared | dedicated} 
SERVER = {shared | dedicated}.
If SERVER=shared is specified in the CONNECT_DATA parameter in the tnsnames.ora file, the server process (UNIX) or thread (Windows) to be used is retrieved from a pool. For example: 
(CONNECT_DATA=
   (SERVER=shared)
)
When SERVER=shared, this setting allows there to be fewer processes than the number of connections, reducing the need for server resources. When SERVER=dedicated, a server process is created to service only that connection. When that connection ends, so does the process (UNIX) or thread (Windows).
ServiceName = service_name 
SERVICE_NAME = service_name
The database service name that specifies the database used for the connection. The service name is a string that is the global database name—a name that typically comprises the database name and domain name. For example:
sales.us.acme.com
The service name is specified in the CONNECT_DATA parameter. For example:
(CONNECT_DATA=
   (SERVICE_NAME=sales.us.acme.com)
)
This parameter is mutually exclusive with the SID attribute and is useful to specify connections to an Oracle Real Application Clusters (RAC) system rather than a specific Oracle instance.
SID = SID 
SID = SID
The Oracle System Identifier (SID) that refers to the instance of the Oracle database running on the server. The default Oracle SID that is configured when installing your Oracle database software is ORCL. The SID is specified in the CONNECT_DATA parameter. For example:
(CONNECT_DATA=
   (SID=ORCL)
)
This parameter is mutually exclusive with the SERVICE_NAME attribute.

For more information about configuring tnsnames.ora files, refer to your Oracle documentation.