Duplicate sid installation in oracle and repeated oraclesid

Duplicate sid installation in oracle and repeated oraclesid

After Oracle is uninstalled, it is installed again. If the configured SID is the same, "the specified SID already exists on the local machine. Please specify a different SID ."

SID Introduction
The SID, also known as Security Identifiers, is a unique number that identifies users, groups, and computer accounts. When this account is created for the first time, a unique SID will be published for each account on the network. The internal process in Windows 2000 references the account SID instead of the account user or group name. If you create an account, delete the account, and then use the same user name to create another account, the new account will not have the permissions or permissions authorized to the previous account, the reason is that the account has different SID numbers. A security identifier is also called a Security ID or SID.

Role of SID
After the user passes the verification, the login process will give the user an access token, which is equivalent to the user's access to system resources. When the user attempts to access system resources, the access token is provided to Windows NT, then, Windows NT checks the access control list on the object you are attempting to access. If the user is allowed to access the object, Windows NT will assign the appropriate access permissions to the user.
The access token is provided by the login process when the user passes the verification. Therefore, to change the user's permissions, You need to log out and log on again to obtain the access token again.

SID number
If there are two users with the same SID, the two accounts will be identified as the same account. In principle, if the account is not added, the same SID will be generated, in general, SID is unique. It is determined by the computer name, current time, and the total CPU time consumed by the current user State thread to ensure its uniqueness.
A complete SID includes:
• Security description for users and groups
• 48-bit ID authority
• Revised Version
• Variable verification value Variable sub-authority values
Example: S-1-5-21-31044058 8-2 500 36847-5 803 895 05-500
Let's analyze this important SID first. The first item S indicates that the string is SID; the second item is the SID version number. For 2000, this is 1; then the identifier authority (identifier authority ), for accounts within 2000, the Authority is NT and the value is 5. Then represents a series of sub-authority. The first few items indicate the domain, and the last one indicates the account and group in the domain.

SID acquisition
　　Start-run-regedit32-HKEY_LOCAL_MACHINESAMSAMDomainsBuiltinAliasesMembersFind the code for the local domain, and expand the code to obtain the list of all SID IDs of the local account.
Many of these values are fixed. For example, if the first 500 F4 (hexadecimal) is converted to in decimal format, it indicates that it is the Built-in administrator account created by the system, the conversion from 000001F5 to 10th is 501, that is, the GUEST account. For details, refer to the list below.
This item can be fully controlled by system by default, which is why we need the Shell of a System Cmd, of course, if you have sufficient permissions, you can add the account you want to add.
Or use the Reg tool of Support Tools:
Reg query "HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionProfileList
There is also a way to obtain the correspondence between SID and User Name:
1. Regedit32:
HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersion ProfileList
2. At this time, you can see the SID value in the left-side window, and you can see the usernames associated with different SID in the right-side window ProfileImagePath,
For example, % SystemDrive % Documents and SettingsAdministrator. momo corresponds to the Administrator SID of the local machine.
% SystemDrive % Documents ents and SettingsAdministrator. domain this is the administrator account of the corresponding domain
In addition, Microsoft's ResourceKit also provides the tool getsid, which is also included in the sysinternals toolkit. In fact, the principle is to read the registry value, which saves some trouble.

Repeated Oracle SID Solution
After Oracle is uninstalled, it is installed again. If the configured SID is the same, "the specified SID already exists on the local machine. Please specify a different SID ."
Implementation Method:
1. Choose "start"> "Settings"> "Control Panel"> "Administrative Tools"> "services" to stop all Oracle services.
2. Start-> Program-> Oracle-OraHome81-> Oracle Installation Products-> Universal Installer uninstalls all Oracle Products, but the Universal Installer cannot be deleted.
5. Run regedit, select HKEY_LOCAL_MACHINE \ SOFTWARE \ ORACLE, and press del to delete the entry.
6. Run regedit and select HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services. Scroll through the list and delete all Oracle entries.
7. Run regedit, HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Eventlog \ Application to delete all Oracle entries.
8. Choose "start"> "Settings"> "Control Panel"> "system"> "advanced"> "environment variable" to delete Oracle settings in the environment variables CLASSPATH and PATH.
9. Delete all groups and icons related to Oracle from the desktop, STARTUP group, and program menu.
10. Delete \ Program Files \ Oracle directory
11. restart the computer to completely delete the Oracle directory.
12. Delete Oracle-related files, select the default Oracle directory C: \ Oracle, delete the entry directory and all subdirectories, and run the Windows 2000 directory (generally C: \ WINNT) to delete the following file ORACLE. INI, oradim73.INI, oradim80.INI, oraodbc. ini and so on.
13. If the [ORACLE] Tag segment exists in the WIN. ini file, delete it.
14. If necessary, delete all Oracle-related ODBC DSN
15. In Event Viewer, delete Oracle-related logs.
Note:
Specifically, objects 6 and 7 are the key objects to be deleted. Normally, objects 5 are easy to be deleted, but 6 and 7 are not easy to be found.
If some DLL files cannot be deleted, You can restart and start a new installation,
During installation, select a new directory. After the installation is completed and restarted, the old directory and files can be deleted.