Oracle Connection Database error: Ora-01034:oracle not available (Oracle does not exist), ora-27101:shared memory realm does not exist

It takes a day and a half to resolve the client connection to the Oracle database on the server side, unable to connect the problem. Ora-01034:oracle Not available (ORACLE does not exist), ora-27101:shared memory realm does not exist analysis:
A few days ago you can also connect to the database, but yesterday, the local no reason to connect to the server database. Many people on the internet say that the cause of this problem is abnormal shutdown
, the database is not shut down before shutting down the computer. My company said in the last few days did someone restart the computer, as is the reason it, there is time must be the real reason to find out.
The following main task is to solve the problem first. Detailed procedures for encountering problems:

Access data via Plsql error: Ora-01034:oracle not available (ORACLE does not exist), ora-27101:shared memory realm does not
exist (the shared memory domain does not exist); Log in with the program also reports this error.

When you encounter this problem, most people first think about checking the server configuration file for problems, so open your Oracle installation path (this must be the server side,
Because the server has a listener file Listener.ora, the client has only Sqlnet.ora and Tnsnames.ora two files) the Admin folder under the main directory has three files (
My server-side installation path is: E:\opt\oracle\product\11.2.0\dbhome_1\NETWORK\ADMIN), respectively: Listener.ora and Sqlnet.ora and
Tnsnames.ora. Open Sqlnet.ora and Tnsnames.ora two files matching local (that is, your local Oracle Client home directory) Sqlnet.ora and
Tnsnames.ora, check that the IP and prot of the two Tnsnames.ora are consistent and must be the same. Below I share under I can normally access, the server and the client two
All the parameters of the file are configured locally: Sqlnet.ora Local: Tnsnames.ora server: Sqlnet.ora server: Tnsnames.ora as follows:

The local client Sqlnet.ora configuration file is all copy as follows:

Sqlnet. Authentication_services= (NTS)

The server-side Sqlnet.ora configuration file is all copied as follows:

Sqlnet. Authentication_services= (NTS)

NAMES. Directory_path= (Tnsnames,hostname)

Adr_base = E:\opt\oracle\product\11.2.0\dbhome_1\log

The same is true for the local client Tnsnames.ora and server Tnsnames.ora: The Tnsnames.ora configuration file is all copied as follows:

# Tnsnames.ora Network Configuration File:c:\instantclient_12_1\tnsnames.ora
# Generated by Oracle configuration tools.
CCNF2008 =
(DESCRIPTION =
(Address_list =
(ADDRESS = (PROTOCOL = TCP) (HOST = 180.166.155.134) (PORT = 1521))
)
(Connect_data =
(service_name = ccnf_2008)
)
)
The preceding asterisk can be ignored. CCNF2008 is the local client connection database alias, Plsql login entry, the database input box is to fill it out. prot=1521 not
Use more to say. The value of service_name is that ccnf_2008 is the name of the database you instantiate on the server. Other parameters are copied.

All copy of the Listener.ora file on the server is as follows:
Sid_list_listener =
(Sid_list =
(Sid_desc =
(Global_dbname = ccnf_2008)
(Oracle_home = E:\opt\oracle\product\11.2.0\dbhome_1)
(Sid_name = ccnf_2008)
)
)
LISTENER =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP) (HOST =180.166.155.134) (PORT = 1521))
)

Adr_base_listener = E:\opt\oracle\product\11.2.0\dbhome_1\log

Check the above three files IP, port, and other parameters are matched can be excluded is not the configuration file reasons.

After you exclude the profile reason, you need to use the Netmanager Manager to test whether the connection was successful, and if the user logon test succeeds, the external telnet ip+ port command
The connection failed, indicating that the network port is not open to the outside, need to establish port 1521 inbound rules. If not yet, go to cmd, command: Lsnrctl stop stop
Listen, restart the monitor again: Lsnrctl start; And then into SQL operation: Sqlplus/nolog execution, Conn/as sysdba to connect data as Administrator
Library startup starts the database, and if it has been started unload the data shutdowm immediate shut down the database and then startup. Telnet IP + port again on the external network,
If not, just: Source network lookup: http://blog.csdn.net/inthirties/article/details/4558769 the most back method
1. Open the Registration form
2. Locate the [hkey_local_machinesoftwareoraclekey_oradb10g_home1] Directory
Add a string value below it
Key: Use_shared_socket
Value: TRUE
3. Restart the Monitoring service

If the above steps are not working, the most likely cause is the distinction between IP and machine name and 127.0.0.1. So, in C:\Windows\System32\drivers,
\ETC, open the Hosts file and add a map. 127.0.0.1 IP address. After setting the completion mapping, restart the listening, startup database. I was through this
Steps to solve the problem.