- What is SQL*Net?
Answer:
SQL*NET is Oracle's client/server middleware product that offers transparent connection from client tools to the database or from one database to another.
- What is TNS?
Answer:
TNS or Transparent Network Substrate is Oracle's networking architecture.TNS provides a uniform application interface to enable network applications to access the underlying network protocols transparently.
The TNS architecture consists of three software components: TNS-based applications, Oracle Protocol Adapters, and networking software like TCP/IP.
- How does one configure SQL*Net?
Answer:
Most people prefer to edit the SQL*Net configuration files by hand.The only "officially supported" configuration method, however, is via the Oracle Network Manager utility.
- How can I produce a trace file?
Answer:
Create/edit your SQLNET.ORA file.You will find the SQLNET.ORA file in one of the following locations (SQL*Net V2 searches for it in this order):
- Directory pointed to by the TNS_ADMIN parameter ($TNS_ADMIN on Unix)
- /var/opt/oracle (Unix only)
- $ORACLE_HOME\network\admin directory
It should contain the following lines to produce a trace file:
trace_level_client=16
trace_unique_client=yes
- How can I set up a dedicated server?
Answer:
Set the dedicated server option in your database connects string.ie.
SQLPLUS SCOTT/TIGER@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP) (PORT=1521)
(NODE=yourServerName)) (CONNECT_DATA=(SID=yourSid) (SERVER=DEDICATED)))
or edit your TNSNAMES.ORA file and add the (SERVER=DEDICATED) part in the CONNECT_DATA list.
- Can I upgrade to SQL*Net V2 if I still have V1 clients?
Answer:
SQL*Net V1 cannot talk with SQL*Net V2, and vice versa.The only way to overcome this problem is to run SQL*Net V1 and V2 simultaneously on the same database server.You can then install SQL*Net V2 on your clients as time permits.SQL*Net V1 and V2 can coexist on the same server, or on the same client.
You can also list V1 connect strings in your TNSNAMES.ORA file.
Eg:
ORA1_NET1 = T:machine_name/port:database_name
- How can I enable dead connection detection?
Answer:
Dead database connections can be detected and killed by SQL*Net if you specify the SQLNET.EXPIRE_TIME=n parameter in your SQLNET.ORA file.This parameter will instruct SQL*Net to send a probe through the network to the client every n minutes, if the client doesn't respond, it will be killed.
- What different protocol drivers are supported?
Answer:
These are the main SQL*Net protocol adapters supported by Oracle:
- IBM's VTAM
- DEC Net
- IBM's LU 6.2
- Named Pipes
- TCP/IP
- Novell's IPX/SPX
- IBM MVS Cross Memory
- NetBEUI
- Can one get connected to a database regardless of machine failure?
Answer:
With SQL*Net V2 you can connect to a database, even if some kind of physical failover occurred.Look at the following example:
oradb1 = (DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS =
(COMMUNITY = TCP_COMM)
(PROTOCOL = TCP)
(HOST = Machine01))
(ADDRESS =
(COMMUNITY = TCP_COMM)
(PROTOCOL = TCP)
(HOST = Machine02)))
{CONNECT_DATA=(
(SID=oradb1))))
Suppose Machine01 is down, then every new SQL*NET connection using service oradb1 will automatically login to Machine02.However, there is one restriction, the SID must be the same on both machines.This feature can provide guaranteed login for application servers and the Oracle Parallel Server.
