Security strategy for Oracle Database (1)
Oracle is a relational database management system, which is powerful and excellent in performance in today's large database management system. In the MIS system we develop, Oracle7.3 database is selected. Under normal circumstances, the Oracle database guarantees the security and stability of the data, providing the user with the correct data, but due to the fault of the computer system (hardware failure, software failure, network failure and system failure) affects the operation of the database system, affecting the database The correctness of the data, even damages the database, making all or part of the data in the database, and the entire system will be in a state of paralysis. Therefore, how to ensure that the security of the Oracle database is an important part of the entire MIS system security.
---- Oracle Database Security Policy includes backup and recovery of the database, user role management.
--- First, the structure used by the database backup
---- Oracle Database Use several structures to protect data: database backup, log, rollback segment, and control files.
---- 1 . The database backup is composed of an operating system backup that makes up the physical file of the Oracle database. Database recovery is performed when the media is fault, and the desired data file or control file is restored by the backup file.
---- 2 . Each Oracle database instance provides a log, and all modifications made in the database. Each running Oracle database instance has an online log, which works with the Oracle background process LGWR and immediately records all modifications made by this instance. Archive (offline) log is optional, an Oracle Database Instance Once the online log is filled, the online log archive can be formed. The archived online log files are uniquely identified and merged into archive logs.
---- 3. Rollback segments are used to store the old values of the values modified by the ongoing transaction (uncommitted transaction), which is used to undo any non-commit changes during database recovery.
---- 4. Control files, typically used to store the physical structure of the database. Some status information in the control file is used to guide Oracle during instance recovery and media recovery.
Second, online log
---- Each instance of an Oracle database has a associated online log. A online log consists of multiple online log files. Online Redo Log File fills in the log entry (Redo Entry), the data recorded by the log entry is used to refactor all modifications to the database.
Third, archive log
---- ORACLE To archive the filled online log file group, you want to establish an archive log. It has the following uses for database backups and recovery:
---- 1 . Database backups and online and archive log files, which can ensure that all submitted things can be restored in the operating system and disk failure.
---- 2 . Under the database opening and normal system, if the archive log is permanently saved, the online backup can be made and used.
---- Database can run in two different ways: noarchiveLog mode or ArchiveLog mode. The database cannot be filed in the NOARCHIVELOG mode. If the database is running in the ArchiveLog mode, the archive of the online log can be implemented.
Oracle Database Security Strategy (2)
Fourth, Oracle's backup feature
---- Oracle backup includes logical backup and physical backup.
---- 1 . Logical backup
---- Database logic backup contains reading a database recordset and writing a recordset into a file.
---- (1) Output (export) output can be the entire database, specify a user or specified table. ---- (2) Input (IMPORT) Enter the binary dump file established to read and execute its command.
---- 2 . Physical backup
---- Physical Backup contains copies that make up the database regardless of its logic.
---- Oracle supports two different types of physical file backups: offline backup and online backups.
---- (1) Offline backup
---- Offline backup is used when the database is already close, the database is in "offline", back up the following files:
All data files
All control files
All online logs
INIT.ORA (optional)
---- (2) Online Backup
---- Online backup can be used to back up any databases operating in ArchiveLog mode. In this way, the online log is archived, and a complete record of all jobs is created inside the database.
---- Online backup process has a powerful function. First, a complete time point is provided to recover. Second, the database is allowed to keep open when the file system is backed up.
---- Comparison of the characteristics of backup mode
Mode type recovery characteristics
Export logic can restore any database objects to the output
Offline backups can restore the database to a closed state: If the database is running in the ArchiveLog mode, it can restore the status of any point in time.
ONLINE Backups Physics
Oracle Database Security Policy (3)
V. Role Management of Oracle Database
---- Oracle Database System Basic Measures taken by Using Role Management Database Security:
By verifying user names and passwords, preventing non-Oracle users from registering to Oracle databases and illegally accessing the database.
A certain permissions are granted, restrict the power of the user to manipulate the database.
Grant users' access execution permissions for database entities, prevent users from accessing unauthorized data.
Provide database entity access audit mechanisms to enable database administrators to monitor access conditions of data in the database and the usage of system resources.
Use view mechanisms to limit rows and columns of access base tables.
Security strategy for Oracle Database (4)
---- Security policy for Oracle database in MIS system instance
---- Since there are three ways of Oracle database backups, each way has different recovery characteristics, so integrated databases and file system backups, integrated logic backups, and physical backups.
First, backup strategy
1 . In the operating system level, use a large-capacity disk array, which automatically distributes each database file through each physical disk through the disk image technology. Thus, when a disk is physically damaged, the operating system automatically triggered an image disk to replace the failure disk, and ensure the normal operation of the database.
Since we use a dual server, a backup database is retained on another server. The backup database has the same parameter status as the database being used, so in the database failure, only the restoration time is shortened to minimize the recovery time.
Keep multiple control files backups on multiple different physical disks. Control files are used to boot Oracle during database recovery, so keep multiple control files, ensuring that the available control files can be used for database recovery after the disk failure occurs.
Make the database in the ArchiveLog (archive) mode, the archive log is stored on another image logical disk. A online backup operation per night, back up all data files, all archive log files, a control file.
Output operation per week.
Second, recovery strategy
---- 1 . Instance failed
---- Recovery from an instance failure is automatic. Example failure is generally caused by the server failure. When the database instance fails, restart the server, launch the database, Oracle check the data file and online log file, and synchronize all files to the same point in time.
---- 2 . Disk failure
---- If the loss is the control file, just turn off the database, copy a copy from the place where the control file is retained.
---- If the data file is lost, you can recover the online backup of the previous day, the steps are as follows:
---- 1) There is a position where the lost files are lost from the backup.
---- 2) Load the database
---- 3) Restore Database
---- 4) Open the database
---- 3. Error Delete or modify the object
---- In this case, it is generally desirable to return to the time point before the error occurred. This is called time point recovery. The steps to complete the recovery are as follows:
---- 1) From the current database output (import), input (import) to the standby database, allow the standby database to be consistent with the current database.
---- 2) Time point before scrolling the spare database to the error occurred.
---- 3) Output of logical objects affected from the alternate database.
---- 4) Use the output file generated by the previous step to enter those affected objects to the current database.
Third, user role management
---- 1 . Different user roles are granted separately by working nature of all clients.
---- 2 . For different user roles, different database object access rights are granted according to the data source used.
---- Based on the above security strategy, it is possible to prevent illegal users from accessing the database, restricting the permissions of legitimate users to manipulate the database; if the database will not lose any data after the failure, and enable the database to quickly restore the failure At that point in point, the maximum guarantee guarantees the security of the data and the continuous operation of the entire system.
