I3306 – Database II
Chapter 4 - Oracle XE 11.2
Administration
References
https://docs.oracle.com/cd/E17781_01/server.112/e18804/toc.htm
https://docs.oracle.com/cd/E11882_01/server.112/e22490/dp_overview.htm#SUTIL100
Chapter Outline
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Starting Up and Shutting Down
Connecting to the Database
Managing Database Memory
Managing Database Storage
Managing Users and Security
Data Dictionary
Monitoring the Database
Viewing Database Version and Globalization
Information
• Exporting and Importing Metadata and Data
• Baking Up and Recovering
Dr. Michel Nabaa
Oracle XE 11.2 Administration
2
Starting Up
• Oracle Database XE starts up automatically immediately
after installation and after each system restart. Thus, there
is no need to start up the database unless you previously
shut it down.
• To startup Oracle XE
– Click Start, Programs (or All Programs), Oracle Database 11g
Express Edition, and then select Start Database.
Or
– At the operating system prompt, enter
SQLPLUS / AS SYSDBA
SQL> STARTUP
• To exit the SQL command line
– SQL> EXIT
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Shutting Down
• Click Start, Programs (or All Programs), Oracle
Database 11g Express Edition, and then select
Stop Database.
Or
• At the operating system prompt, enter
– SQLPLUS / AS SYSDBA
– SQL> SHUTDOWN IMMEDIATE
Dr. Michel Nabaa
Oracle XE 11.2 Administration
4
Connecting to the Database
• 1. Locally
• Using the SQL Command Line
– Click Start, point to Programs (or All Programs), point to
Oracle Database 11g Express Edition, and then select Run
SQL Command Line.
SQL> CONNECT username/password
Or
• At the operating system prompt, enter
– SQLPLUS
SQL> CONNECT username/password
• Using SQL Developer
– Create Database Connections
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Connecting to the Database
• 2. Remotely
• At the operating system prompt, enter
– SQLPLUS
SQL> Connect
username/password@[//]host[:port][/service_name]
// is optional
– host is host name or IP address of the computer running Oracle
XE
– port (optional) TCP port number where Oracle Net listener is
listening.
• If not specified, the default port number 1521 is assumed.
– service_name (optional) for Oracle Database XE, service name is
XE.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Managing Database Memory
• Memory allocation Overview
• Automatic Memory Management
• SGA and PGA sizes
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Memory allocation Overview
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Automatic Memory Management
(AMM)
• Automatic Memory Management in Oracle
Database XE usually provides the best memory
configuration based on your resources and
workload.
• It dynamically exchanges memory between SGA
and PGA as needed to meet processing demands
and tunes the sizes of the individual SGA
components and the sizes of the individual PGAs.
• Automatic Memory Management cannot be
disabled.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
9
SGA and PGA sizes (1)
• Default sizes for SGA and PGA are set upon installation.
• The maximum amount of memory allowed for the SGA
and PGA Aggregate is 1 gigabyte (GB).
• Starting Oracle 11g, AMM is enabled and
memory_target parameter is set.
• If memory_target is set to non zero value and :
– sga_target and pga_aggregate_target are set to 0, then
60% of memory mentioned in memory_target is allocated
to SGA and the remaining 40% is kept for PGA.
– sga_target and pga_aggregate_target are set to non-zero
values, then these values will be considered minimum
values.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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SGA and PGA sizes (2)
• The only circumstances under which you should need
to change SGA and PGA Aggregate sizes are the
following:
– You add physical memory to the computer running Oracle
Database XE and want to allocate more to the database.
– You received an error due to insufficient memory.
• in SGA
ORA-04031: unable to allocate n bytes of shared memory
ORA-00379: no free buffers available in buffer pool...
• in PGA
ORA-04030: out of process memory when trying to allocate n
bytes
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Changing SGA and PGA sizes (1)
• In SQL Developer, click View, then DBA to display the DBA
navigator.
• In the DBA navigator, expand the SYSTEM connection,
expand Database Configuration, and click Initialization
Parameters.
• Note the current values for pga_aggregate_target and
sga_target, and calculate the desired new values. Assume
that the desired new values are 140 megabytes for
pga_aggregate_target and 400 megabytes for sga_target.
• In the Connections navigator, select the SYSTEM
connection; and if a SQL Worksheet is not already open for
that connection, rightclick SYSTEM and select Open SQL
Worksheet.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Changing SGA and PGA sizes (2)
• Enter the following command lines:
– ALTER SYSTEM SET pga_aggregate_target = 140 M;
– ALTER SYSTEM SET sga_target = 400 M;
• Run Script icon to execute these statements.
• At the next convenient time, shut down and restart the
database to enable the SGA size changes to take effect.
• SHOW SGA;
Do not set any memory-related parameters unless you
fully understand the consequences.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Managing Database Storage
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The Database Storage Structures
Monitoring Storage Space Usage
Compacting Storage
Viewing redo Log Files
Managing the Flash recovery Area
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Oracle XE 11.2 Administration
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The Database Storage Structures
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Oracle XE 11.2 Administration
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Monitoring Storage Space Usage (1)
• Oracle Database XE 11.2 is limited to 11GB of
user data
• To check and monitor the storage space used
1. In SQL Developer, click the Reports navigator tab, and
expand the hierarchy as follows: All Reports, then Data
Dictionary Reports, then Database Administration,
then Storage.
2. Under Storage, click Free Space, then select a
database connection for a privileged user such as
SYSTEM
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Monitoring Storage Space Usage (2)
• If you notice that free space is becoming low
1. For each schema:
– Log in as the schema owner.
– Drop (delete) unused database objects.
– Purge the recycle bin.
2. Compact storage.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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The Recycle Bin
• The recycle bin is a data dictionary table containing
information about dropped objects.
SELECT Value FROM V$parameter WHERE Name =
'recyclebin';
ALTER SYSTEM SET recyclebin = ON;
Or
ALTER SESSION SET recyclebin = ON;
• In SQL Developer, in the Connections navigator, you
can
– view the contents of the recycle bin ,
– restore dropped objects, and
– purge objects from the recycle bin.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Compact Storage
• Objects with fragmented free space result in much
wasted space.
• The preferred way to defragment and reclaim this
space is to perform an online segment shrink.
• Use Segment Advisor to identify segments that would
benefit from online segment shrink.
• If the Segment Advisor determines that an object has a
significant amount of free space, it recommends online
segment shrink.
ALTER TABLE employees ENABLE ROW MOVEMENT;
ALTER TABLE employees SHRINK SPACE COMPACT;
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Viewing Redo Log Files
1. In SQL Developer, click View, then DBA.
2. Expand a SYSTEM connection in the DBA
navigator; then expand Storage and select
Redo Log Groups.
3. Select any redo log group to see its location,
type, and whether it was created in the flash
recovery area.
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Oracle XE 11.2 Administration
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Managing the Flash Recovery Area(1)
Monitoring flash recovery area available space
• To determine the current available space in the flash recovery area, as a
system user run the SQL query:
SELECT NAME, TO_CHAR(SPACE_LIMIT, '999,999,999,999') AS
SPACE_LIMIT, TO_CHAR(SPACE_LIMIT - SPACE_USED +
SPACE_RECLAIMABLE, '999,999,999,999') AS
SPACE_AVAILABLE, ROUND((SPACE_USED SPACE_RECLAIMABLE)/SPACE_LIMIT * 100, 1) AS
PERCENT_FULL
FROM V$RECOVERY_FILE_DEST;
• Name indicates the current flash recovery area location.
• SPACE_LIMIT indicates the current flash recovery area maximum size.
• SPACE_AVAILABLE indicates the space available for storing new backups
and archived redo logs.
• PERCENT_FULL indicates the current percentage of flash recovery area
space used for backups and archived redo logs.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Managing the Flash Recovery Area(2)
Setting the flash recovery area location
• To change the flash recovery area location,
connect as sysdba and :
– Run the SQL command:
ALTER SYSTEM SET DB_RECOVERY_FILE_DEST = 'new_path‘;
– Run PL/SQL script movelogs.sql that moves the online
redo log files to the new flash recovery area location
and drops the log files from the old location. On the
drive where Oracle XE is installed, movelogs.sql is in
the directory :
C:\oraclexe\app\oracle\product\11.2.0\server\rdbms\admin
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Managing the Flash Recovery Area(2)
• Do not manually delete the contents of the
old flash recovery area using operating system
utilities.
• Make the backups in the old flash recovery
area location obsolete by backing up your
database twice after you change the location
of the flash recovery area.
• Only the two most recent backups and
accompanying archived redo logs are retained.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Managing the Flash Recovery Area(3)
Changing the flash recovery area size
• To change the flash recovery area size,
connect as sysdba and run the SQL command:
ALTER SYSTEM SET
DB_RECOVERY_FILE_DEST_SIZE = new_size;
where new_size is of the format nK
(kilobytes), nM (megabytes) or nG (gigabytes).
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Managing Users and Security
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About User Accounts
User privileges and roles
Administrative Accounts and Privileges
The SYS and SYSTEM Users
The SYSDBA system Privilege
Logging in as an Administrator
Changing Administrative User Passwords
Managing Database Users
Predefined User Accounts
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Oracle XE 11.2 Administration
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About User Accounts
• A user account is identified by a user name and defines the
user's attributes, including the following:
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Password for database authentication
Privileges and roles
Default tablespace for database objects
Default temporary tablespace for query processing workspace
• When you create a user, you are also implicitly creating a
schema for that user. A schema is a logical container for the
database objects (such as tables, views, triggers, and so on)
that the user creates.
• When you drop (delete) a user, you must either first drop
all the user's schema objects, or use the cascade feature.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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User privileges and roles
• Two main types of user privileges:
– System privileges are privileges given to users to allow
them to perform certain functions that deal with
managing the database and the server, for example
CREATE USER, CREATE TABLE, CREATE SESSION, …
– Object privileges allow users to perform certain
actions upon certain database objects, where
database objects are things like tables, stored
procedures, indexes, etc …, for example DELETE
and/or SELECT from a particular table
• GRANT statement is used to grant privileges
• REVOKE statement is used to revoke privileges
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Oracle XE 11.2 Administration
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User privileges and roles
• A role is a named group of related privileges
• System and object privileges are granted to roles and
roles are granted to users.
• Predefined roles in Oracle XE
– DBA role enables a user to perform most administrative
functions, ex creating users and granting privileges;
creating and granting roles; creating and dropping schema
objects in other users' schemas; and more. It grants all
system privileges. It is by default granted to user SYSTEM.
You should be very cautious about assigning the DBA role
to any other database users.
– Use of the CONNECT and RESOURCE roles is discouraged.
• Instead, grant only those privileges that the specific user will need.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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The SYSTEM and SYS Users (1)
• Administrative user accounts, automatically
created when you install Oracle Database XE.
They are both created with the password that
you supplied upon installation.
• SYSTEM :
– Automatically granted the DBA role
– Used to perform all administrative functions other
than starting up and shutting down the database.
– Never use the SYSTEM schema to store tables of
interest to non-administrative users.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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The SYS and SYSTEM Users (2)
• SYS :
– automatically granted the DBA role
– Owns the base tables and views for the database data
dictionary
– the default schema when you connect as SYSDBA
– Tables in the SYS schema are manipulated only by the
database.
– No one should create any tables in the schema of user
SYS.
– Database users should not connect to the Oracle
database using the SYS account.
– User SYSTEM is preferred for all administrative tasks
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Oracle XE 11.2 Administration
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The SYSDBA System Privilege
• SYSDBA is a system privilege assigned only to
user SYS to perform high-level administrative
tasks such as starting up and shutting down
the database.
• To connect to the database with the SYSDBA
privilege from the SQL Command Line:
• SQL > connect sys/password as sysdba
password is the password for the SYS user
account.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Logging In as an Administrator
• Three ways to log in to Oracle Database XE to
perform administrative tasks:
– Log in as user SYSTEM
– Log in as a user who has been granted the DBA
role
– Log in and connect to the database as SYSDBA
SQL> CONNECT SYS/<password> AS SYSDBA;
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Changing Administrative User
Passwords
• To change the password for user SYS or
SYSTEM Using the SQL Command Line
– Connect to the database as SYSDBA
– Enter one of the following commands:
• ALTER USER SYS IDENTIFIED BY newpassword;
• ALTER USER SYSTEM IDENTIFIED BY newpassword;
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Managing Database Users
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Creating users
Altering users
Locking and unlocking user accounts
Expiring a user password
Dropping users
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Managing Database Users
• To perform the managing database users
operations in the SQL Developer Connections
navigator
1. Open a connection to the SYSTEM user.
2. In the nodes under this SYSTEM connection, expand
Other Users.
– To create a new database user, right-click the Other
Users node.
– To perform an action on a database user, right-click
that user in the hierarchy and select the appropriate
command (Edit User or Drop User).
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Predefined User Accounts
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Oracle XE 11.2 Administration
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Data Dictionary
• Set of read-only tables and views containing
information about the database including
schemas, users, privileges, and even auditing
data.
– ‘Metadata’ information is stored inside the
database
– Can be read and queried just like any standard
table
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Oracle XE 11.2 Administration
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Data Dictionary
• More than 1200 data dictionary views in 11g
– Static views ex USER_TABLES
– Dynamic views ex V$PARAMETER
– Global dynamic views ex GV$PARAMETER
– Undocumented views ex X$KSPPI
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Oracle XE 11.2 Administration
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Static Views
• Contain data about objects, privileges, users, etc
• Contents change with DDL operations
• Three types
– USER_
• Contains only information about current user objects
• Ex USER_TABLES
– ALL_
• Contains only information about current user objects and objects
he is privileged to use
• Ex ALL_TABLES
– DBA_
• Contains all objects, use restricted to DBA
• Ex DBA_TABLES
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Common Static DBA Views
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Oracle XE 11.2 Administration
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Dynamic Performance Views
• They are continuously updated while a
database is open and in use
• Their contents relate primarily to performance.
• Common dynamic views:
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Oracle XE 11.2 Administration
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Miscellaneous Views
• SESSION_PRIVS
– Active session privileges
• DICTIONARY
– Names and descriptions of all data dictionary views
available to the current user
• DICT_COLUMNS
– Column descriptions for views available to the current
user
• TABLE_PRIVILEGES
– Object privileges for the current user
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Oracle XE 11.2 Administration
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Monitoring the Database
• As an administrator, you can monitor the
activities of the database and its users.
– Monitoring Sessions
– Monitoring the Top SQL Statements
– Monitoring Long Operations
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Oracle XE 11.2 Administration
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Monitoring Sessions
• SQL Developer enables you to monitor the
current database sessions:
– to determine the users who are currently logged
in to the database
– to determine what applications the users are
running.
– To kill a session
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Oracle XE 11.2 Administration
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Viewing Sessions
1. In SQL Developer, click Tools, then Monitor
Sessions.
2. In the Select Connection dialog box, select a
connection to SYSTEM (or another account with
full DBA privileges). A Sessions tab is displayed.
3. (Optional) Right-click in any row in the display,
and explore the options available as shown in
the context menu commands, which include
Trace Session, Kill Session, and Find/Highlight (to
search for rows in the grid that contain a
specified text string).
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Monitoring the Top SQL Statements (1)
• The "top" SQL statements are the SQL statements
that:
– are executed most often
– use more system resources than other SQL
statements, or
– use system resources more frequently than other SQL
statements.
• Viewing the top SQL statements enables you to
focus your SQL tuning efforts on the statements
that can have the most impact on database
performance.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Monitoring the Top SQL Statements (2)
• To monitor the top SQL statements:
1. In SQL Developer, click the Reports navigator
tab, and expand the hierarchy as follows: All
Reports, then Data Dictionary Reports, then
Database Administration, then Top SQL.
2. Under Top SQL, select any of the listed "Top
SQL by“ reports: Buffer Gets, Buffer
Gets/Rows Proc, CPU, Disk Reads, Executions,
or Waits.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Killing a Session
• Killing a Session logs it off and disconnects the user running
the session.
• Reasons to kill a session :
1. The session is not responding.
2. You want to perform an administrative function that
requires all users to log off first, but the user is not
available to end his or her session.
• To kill a session
1.
2.
3.
In SQL Developer, click Tools, then Monitor Sessions.
In the Select Connection dialog box, select a connection to
SYSTEM (or another account with full DBA privileges).
Right-click in the row for the session to be terminated, and
select Kill Session.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Monitoring Long Operations
• To monitor long operations:
1. In SQL Developer, click the Reports navigator
tab, and expand the hierarchy as follows: All
Reports, then Data Dictionary Reports, then
Database Administration, then Sessions.
2. Under Sessions, select Active Sessions.
3. If you are asked to select a connection, select
one for SYS AS SYSDBA.
4. Check the UP_TIME value for each listed
session, and note any that you consider to be
longer than desired or expected.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Viewing Database Globalization
Information
• To view database version information:
1. In SQL Developer, click the Reports tab on the
left, near the Connections navigator. (If this tab
is not visible, click View, then Reports.)
2. In the Reports navigator, expand Data
Dictionary Reports.
3. Under Data Dictionary Reports, expand About
Your Database.
4. Under About Your Database, click National
Language Support Parameters.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Exporting & Importing Metadata and
Data
• You can export and import metadata (database
object definitions), data, or both metadata and
data in two ways:
1. Using SQL Developer for Exporting and Importing
data
2. Using Other Tools for Exporting and Importing data
• For more convenience, you may want to use SQL
Developer for export and import operations
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Exporting & Importing Metadata and
Data
• Using SQL Developer for Exporting and Importing
data
– Example: Exporting Metadata and Data for a Table
– Example: Importing Metadata and Data Using a Script
File
– Example: Exporting Data to a Microsoft Excel File
– Example: Importing Data from a Microsoft Excel File
https://docs.oracle.com/cd/E17781_01/server.112/
e18804/impexp.htm#ADMQS258
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Exporting & Importing Metadata and
Data
• In SQL Developer, click Tools, then Database
Export.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Backing Up and Recovering
• Backing Up and Restoring the Database
• Viewing and Restoring Historical Data with
Flashback Query
• Recovering Dropped Tables
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Backing Up and Restoring the
Database
• About Backing Up and Restoring the Database
• Enabling ARCHIVELOG Mode for Media Failure
Protection
• Backing Up the Database
• Scheduling Automatic Backups
• Restoring and Recovering the Database
Dr. Michel Nabaa
Oracle XE 11.2 Administration
55
About Backing Up and Restoring the
Database
• Based on protecting the physical files that
make up the database
• Oracle Database XE uses the Recovery
Manager (RMAN) utility
• Oracle Database XE includes backup and
restore scripts to perform a full backup and
restore of the entire database, and store
backup files in the flash recovery area.
• Automatic Management of Backup Storage
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Viewing the Current ARCHIVELOG
Mode Setting
1. Using the SQL Command Line, log in to the
database and connect as SYSDBA
2. Enter the following command:
SELECT log_mode FROM v$database;
3. The LOG_MODE value will be either
ARCHIVELOG (that is, on) or NOARCHIVELOG
(that is, off).
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Oracle XE 11.2 Administration
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Turning on ARCHIVELOG Mode
1.
2.
Using the SQL Command Line, log in to the database and connect as
SYSDBA.
At the SQL Command Line prompt, enter :
SHUTDOWN IMMEDIATE
3.
At the SQL Command Line prompt, enter : STARTUP MOUNT
4.
5.
SQL> ALTER DATABASE ARCHIVELOG;
SQL > ALTER DATABASE OPEN;
The database is now running with the new ARCHIVELOG mode setting.
Change the size of the flash recovery area to at least 15 gigabytes to allow
for the extra space required for archived log files.
ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE = 20G;
6.
7.
To display space limit and used space SELECT * FROM V$RECOVERY_FILE_DEST;
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Oracle XE 11.2 Administration
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Backing Up the Database (1)
• In ARCHIVELOG mode, the provided backup
script performs online backups of a database.
• In NOARCHIVELOG mode, backups are
performed offline.
• Click Start, point to Programs (or All
Programs), point to Oracle Database 11g
Express Edition, and then select Backup
Database.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Backing Up the Database (2)
• Logs containing the output from the last two backups
in Windows are stored in the locations :
– C:\oraclexe\app\oracle\product\11.2.0\server\database\O
XE_BACKUP_CURRENT.LOG.
– C:\oraclexe\app\oracle\product\11.2.0\server\database\O
XE_BACKUP_PREVIOUS.LOG.
• The database backup is stored in the directory
– C:\oraclexe\app\oracle\oradata\XE
• To schedule automatic backups, use any task
scheduling software to run the supplied backup script :
– C:\oraclexe\app\oracle\product\11.2.0\server\bin\Back
up.bat
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Restoring and Recovering the
Database (1)
• In ARCHIVELOG mode, the restore script restores the
backed up database files, and then uses the online and
archived redo log files to recover the database to the state
it was in before the software or media failure occurred.
• In NOARCHIVELOG mode, the restore script restores the
database to its state at the last backup. Any transactions
that took place after the last backup are lost.
• Restore script is lunched by running the Restore Database
command.
• Click Start, point to Programs (or All Programs), point to
Oracle Database 11g Express Edition, and then select
Restore Database.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Restoring and Recovering the
Database (2)
• Restoring and Recovering the Database are based on the
following assumptions:
– A software failure, media (disk) failure, or operator error caused
the loss or corruption of one or more database files, rendering
the database unusable.
– In the flash recovery area, the backup sets and, if in
ARCHIVELOG mode, archived logs, are intact and available.
– If in ARCHIVELOG mode, the online redo logs are intact and
available. If not, the database is restored to the point of the last
transaction included in an archived log.
– The Oracle Database XE host computer and operating system
are operational.
– The Oracle Database XE installed software (binaries) are intact
and operational.
Dr. Michel Nabaa
Oracle XE 11.2 Administration
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Viewing and Restoring Historical Data
with Flashback Query
• The Flashback Query feature of Oracle Database
XE enables you to retrieve data at a point in time
in the past from a table or materialized view. You
can then reconstruct lost data that was deleted or
changed by accident.
• The clause AS OF added to the SELECT statement
specifies either a time or a System Change
Number (SCN). The query then uses the
committed data from the corresponding time.
• SCN is a stamp that defines a committed version
of a database at a point in time.
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Oracle XE 11.2 Administration
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Example: Recovering Data with
Flashback Query
• The example retrieves the state of the record for Hanna at 9:30
a.m., April 4, 2017 and restores Hanna's information to the
employees table.
SELECT * FROM employees AS OF TIMESTAMP TO_TIMESTAMP
('2017-04-04 09:30:00', 'YYYY-MM-DD HH:MI:SS')
WHERE last_name = ‘Hanna';
INSERT INTO employees
(SELECT * FROM employees AS OF TIMESTAMP
TO_TIMESTAMP('2017-04-04 09:30:00', 'YYYY-MM-DD HH:MI:SS')
WHERE last_name = ‘Hanna');
Dr. Michel Nabaa
Oracle XE 11.2 Administration
64