Oracle beginners often encounter errors and Solutions

1. ORA-12541: TNS: No listener cause: No listener is started or the listener is corrupt. If it is the former, use the command to start the listener: netstartOracleOraDb10g_home1TNSListener (the name may be different) to stop the listener: netstopOracleOraDb10g_home1TNSListener; if it is the latter, use netshortati

1. ORA-12541: TNS: No listener cause: No listener is started or the listener is corrupt. If it is the former, use the command to start the listener: net start OracleOraDb10g_home1TNSListener (the name may be different) to stop the listener: net stop OracleOraDb10g_home1TNSListener; if it is the latter, use Net consumer ATI

1. ORA-12541: TNS: No listener

Cause: the listener is not started or damaged.
If it is the former, use the command to start the listener: net start OracleOraDb10g_home1TNSListener (the name may be different) to stop the listener: net stop OracleOraDb10g_home1TNSListener;
If it is the latter, add a listener using "Listener Configuration" in the "Net Configuration Assistant" tool wizard (no information is required, all the way OK. You may need to delete all listeners before adding them !)

2. ORA-12500: TNS: The Listener cannot start a dedicated server process or ORA-12560: TNS: protocol adapter Error

Cause: ORACLE Database Service is not started. Run the net start OracleServiceORCL command (ORADB is the database name. If the problem persists, proceed to the following section.

3. If the database service fails to be started, the registry key value may be corrupted. The best practice is to perform the following two steps:

1) ORADIM-DELETE-SID oradb deletes database service items

2) ORADIM-NEW-SID oradb adds database service items

Note: if an error occurs during this process, restart the computer!

4. ORA-12154: TNS: the service name cannot be resolved

Cause: the network service name of ORACLE is not correctly configured. Use "Local Network Service name Configuration" in the "Net Configuration Assistant" tool Wizard to configure TNS. If the problem persists, proceed to the following section.

5. ORA-1034: TNS: ORACLE unavailable

Cause: the ORACLE Database Service is correctly started, but the database is not opened!

Run the following command:

1) svrmgrl start the Service Manager

2) connect internal logs in as internal

3) startup open the database

6. ORA-12154: TNS: Service name cannot be resolved

Today, manually configure the service name, log on to pl/SQL appeared ORA-12154: TNS: cannot resolve the service name error, previously all manual configuration today to make it inexplicable. Ask a high-handed user, and then use the netca command for verification, and report the error "unexpected characters or text"

C:/Documents and Settings/Administrator> netca

Oracle Net Services Configuration:
ServiceAliasException: Unable to list Net service name: TNS-04404: no error
Caused by: oracle.net. config. ConfigException: TNS-04414: file Error
Caused by: TNS-04605: Invalid Syntax Error: www = (unexpected character or text in or before "w
Ww"
The user terminates the Oracle Net Services configuration. Exit code is-1

It is estimated that a special character or invisible character exists between these two characters, so that similar errors may occur in the future.

After deletion, the configuration is re-configured. Experience Accumulation requires a process.

7. ORA-12560: TNS: protocol adapter Error

The reason may be that the firewall is strong in linux:

# Disable the firewall with iptables-F.