From Ver. 10g / 11g Oracle has also released Data Pump Export and Import tools, which are enhanced versions of original Export and Import tools.
The export dump file contains objects in the following order:
1. Type definitions
2. Table definitions
3. Table data
4. Table indexes
5. Integrity constraints, views, procedures, and triggers
6. Bitmap, function-based, and domain indexes
When you import the tables the import tool will perform the actions in the following order, new tables are created, data is imported and indexes are built, triggers are imported, integrity constraints are enabled on the new tables, and any bitmap, function-based, and/or domain indexes are built. This sequence prevents data from being rejected due to the order in which tables are imported. This sequence also prevents redundant triggers from firing twice on the same data
Invoking Export and Import
You can run Export and Import tool in two modes
Command Line Mode
Interactive Mode
When you just type exp or imp at o/s prompt it will run in interactive mode i.e. these tools will prompt you for all the necessary input. If you supply command line arguments when calling exp or imp then it will run in command line mode
Command Line Parameters of Export tool
You can control how Export runs by entering the EXP command followed
by various arguments. To specify parameters, you use keywords:
Format: EXP KEYWORD=value or KEYWORD=(value1,value2,...,valueN)
Example: EXP SCOTT/TIGER GRANTS=Y TABLES=(EMP,DEPT,MGR)
or TABLES=(T1:P1,T1:P2), if T1 is partitioned table
Keyword Description (Default)
-------------------------------------------------------------------------------------
USERID username/password
BUFFER size of data buffer
FILE output files (EXPDAT.DMP)
COMPRESS import into one extent (Y)
GRANTS export grants (Y)
INDEXES export indexes (Y)
DIRECT direct path (N)
LOG log file of screen output
ROWS export data rows (Y)
CONSISTENT cross-table consistency(N)
FULL export entire file (N)
OWNER list of owner usernames
TABLES list of table names
RECORDLENGTH length of IO record
INCTYPE incremental export type
RECORD track incr. export (Y)
TRIGGERS export triggers (Y)
STATISTICS analyze objects (ESTIMATE)
PARFILE parameter filename
CONSTRAINTS export constraints (Y)
OBJECT_CONSISTENT transaction set to read only during object export (N)
FEEDBACK display progress every x rows (0)
FILESIZE maximum size of each dump file
FLASHBACK_SCN SCN used to set session snapshot back to
FLASHBACK_TIME time used to get the SCN closest to the specified time
QUERY select clause used to export a subset of a table
RESUMABLE suspend when a space related error is encountered(N)
RESUMABLE_NAME text string used to identify resumable statement
RESUMABLE_TIMEOUT wait time for RESUMABLE
TTS_FULL_CHECK perform full or partial dependency check for TTS
TABLESPACES list of tablespaces to export
TRANSPORT_TABLESPACE export transportable tablespace metadata (N)
TEMPLATE template name which invokes iAS mode export
The Export and Import tools support four modes of operation
FULL :Exports all the objects in all schemas
OWNER :Exports objects only belonging to the given OWNER
TABLES :Exports Individual Tables
TABLESPACE :Export all objects located in a given TABLESPACE.
Example of Exporting Full Database
The following example shows how to export full database
$exp USERID=scott/tiger FULL=y FILE=myfull.dmp
In the above command, FILE option specifies the name of the dump file, FULL option specifies that you want to export the full database, USERID option specifies the user account to connect to the database. Note, to perform full export the user should have DBA or EXP_FULL_DATABASE privilege.
Example of Exporting Schemas
To export Objects stored in a particular schemas you can run export utility with the following arguments
$exp USERID=scott/tiger OWNER=(SCOTT,ALI) FILE=exp_own.dmp
The above command will export all the objects stored in SCOTT and ALI’s schema.
Exporting Individual Tables
To export individual tables give the following command
$exp USERID=scott/tiger TABLES=(scott.emp,scott.sales) FILE=exp_tab.dmp
This will export scott’s emp and sales tables.
Exporting Consistent Image of the tables
If you include CONSISTENT=Y option in export command argument then, Export utility will export a consistent image of the table i.e. the changes which are done to the table during export operation will not be exported.
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