Wednesday, September 26, 2012


What Is Data Pump Import?

Data Pump Import (hereinafter referred to as Import for ease of reading) is a utility for loading an export dump file set into a target system. The dump file set is made up of one or more disk files that contain table data, database object metadata, and control information. The files are written in a proprietary, binary format. During an import operation, the Data Pump Import utility uses these files to locate each database object in the dump file set. Import can also be used to load a target database directly from a source database with no intervening dump files. This allows export and import operations to run concurrently, minimizing total elapsed time. This is known as a network import.


Data Pump Import enables you to specify whether a job should move a subset of the data and metadata from the dump file set or the source database (in the case of a network import), as determined by the import mode. This is done using data filters and metadata filters, which are implemented through Import commands.

Invoking Data Pump Import

The Data Pump Import utility is invoked using the impdp command. The characteristics of the import operation are determined by the import parameters you specify. These parameters can be specified either on the command line or in a parameter file.

Note:  Do not invoke Import as SYSDBA, except at the request of Oracle technical support. SYSDBA is used internally and has specialized functions; its behavior is not the same as for general users.

Be aware that if you are performing a Data Pump Import into a table or tablespace created with the NOLOGGING clause enabled, a redo log file may still be generated. The redo that is generated in such a case is generally related to underlying recursive space transactions, data dictionary changes, and index maintenance for indices on the table that require logging.

It is not possible to start or restart Data Pump jobs on one instance in a Real Application Clusters (RAC) environment if there are Data Pump jobs currently running on other instances in the RAC environment.


Data Pump Import Interfaces

You can interact with Data Pump Import by using a command line, a parameter file, or an interactive-command mode.

  • Command-Line Interface: Enables you to specify the Import parameters directly on the command line. For a complete description of the parameters available in the command-line interface.
  • Parameter File Interface: Enables you to specify command-line parameters in a parameter file. The only exception is the PARFILE parameter because parameter files cannot be nested. The use of parameter files is recommended if you are using parameters whose values require quotation marks.
  • Interactive-Command Interface: Stops logging to the terminal and displays the Import prompt, from which you can enter various commands, some of which are specific to interactive-command mode. This mode is enabled by pressing Ctrl+C during an import operation started with the command-line interface or the parameter file interface. Interactive-command mode is also enabled when you attach to an executing or stopped job.

Data Pump Import Modes

One of the most significant characteristics of an import operation is its mode, because the mode largely determines what is imported. The specified mode applies to the source of the operation, either a dump file set or another database if the NETWORK_LINK parameter is specified.

When the source of the import operation is a dump file set, specifying a mode is optional. If no mode is specified, then Import attempts to load the entire dump file set in the mode in which the export operation was run.

Full Import Mode

A full import is specified using the FULL parameter. In full import mode, the entire content of the source (dump file set or another database) is loaded into the target database. This is the default for file-based imports. You must have the IMP_FULL_DATABASE role if the source is another database.

Cross-schema references are not imported for non-privileged users. For example, a trigger defined on a table within the importing user's schema, but residing in another user's schema, is not imported.

The IMP_FULL_DATABASE role is required on the target database and the EXP_FULL_DATABASE role is required on the source database if the NETWORK_LINK parameter is used for a full import.

Schema Mode

A schema import is specified using the SCHEMAS parameter. In a schema import, only objects owned by the specified schemas are loaded. The source can be a full, table, tablespace, or schema-mode export dump file set or another database. If you have the IMP_FULL_DATABASE role, then a list of schemas can be specified and the schemas themselves (including system privilege grants) are created in the database in addition to the objects contained within those schemas.

Cross-schema references are not imported for non-privileged users unless the other schema is remapped to the current schema. For example, a trigger defined on a table within the importing user's schema, but residing in another user's schema, is not imported.

Table Mode

A table-mode import is specified using the TABLES parameter. In table mode, only the specified set of tables, partitions, and their dependent objects are loaded. The source can be a full, schema, tablespace, or table-mode export dump file set or another database. You must have the IMP_FULL_DATABASE role to specify tables that are not in your own schema.

Tablespace Mode

A tablespace-mode import is specified using the TABLESPACES parameter. In tablespace mode, all objects contained within the specified set of tablespaces are loaded, along with the dependent objects. The source can be a full, schema, tablespace, or table-mode export dump file set or another database. For unprivileged users, objects not remapped to the current schema will not be processed.

Transportable Tablespace Mode

A transportable tablespace import is specified using the TRANSPORT_TABLESPACES parameter. In transportable tablespace mode, the metadata from a transportable tablespace export dump file set or from another database is loaded. The datafiles specified by the TRANSPORT_DATAFILES parameter must be made available from the source system for use in the target database, typically by copying them over to the target system. This mode requires the IMP_FULL_DATABASE role.

Network Considerations

You can specify a connect identifier in the connect string when you invoke the Data Pump Import utility. This identifier can specify a database instance that is different from the current instance identified by the current Oracle System ID (SID). The connect identifier can be an Oracle*Net connect descriptor or a name that maps to a connect descriptor. This requires an active listener (to start the listener, enter lsnrctl start) that can be located using the connect descriptor.

The NETWORK_LINK parameter initiates a network import. This means that the impdp client initiates the import request. The server for that request contacts the remote source database referenced by the database link in the NETWORK_LINK parameter, retrieves the data, and writes it directly back to the local database. There are no dump files involved.


Filtering During Import Operations

Data Pump Import provides much greater data and metadata filtering capability than was provided by the original Import utility.

Data Filters

Data filters specify restrictions on the rows that are to be imported. These restrictions can be based on partition names and on the results of subqueries. Each data filter can only be specified once per table and once per job. If different filters using the same name are applied to both a particular table and to the whole job, the filter parameter supplied for the specific table will take precedence.

Metadata Filters

Data Pump Import provides much greater metadata filtering capability than was provided by the original Import utility. Metadata filtering is implemented through the EXCLUDE and INCLUDE parameters. The EXCLUDE and INCLUDE parameters are mutually exclusive.

Metadata filters identify a set of objects to be included or excluded from a Data Pump operation. For example, you could request a full import, but without Package Specifications or Package Bodies.

To use filters correctly and to get the results you expect, remember that dependent objects of an identified object are processed along with the identified object. For example, if a filter specifies that a package is to be included in an operation, then grants upon that package will also be included. Likewise, if a table is excluded by a filter, then indexes, constraints, grants, and triggers upon the table will also be excluded by the filter. To see which objects can be filtered, you can perform queries on the following views: DATABASE_EXPORT_OBJECTS, SCHEMA_EXPORT_OBJECTS, and TABLE_EXPORT_ OBJECTS.


When you specify the ATTACH parameter, you cannot specify any other parameters except for the connection string (user/password). You cannot attach to a job in another schema unless it is already running. If the dump file set or master table for the job have been deleted, the attach operation will fail. Altering the master table in any way will lead to unpredictable results.



Enables you to filter what is loaded during the import operation.



DUMPFILE :   Specifies the names and optionally, the directory objects of the dump file set that was created by Export.




EXCLUDE: Default: none

FLASHBACK_SCN: Default: none

FLASHBACK_TIME: Default: none

FULL : Default: Y

HELP: Default: n

INCLUDE: Default: none

JOB_NAME:  Default: system-generated name of the form SYS_<IMPORT or SQLFILE>_<mode>_NN

LOGFILE: Default: import.log

NETWORK_LINK: Default: none

NOLOGFILE: Default: n

PARALLEL: Default: 1

PARFILE: Default: none

QUERY: Default: none


REMAP_DATAFILE: Default: none.

Changes the name of the source datafile to the target datafile name in all SQL statements where the source datafile is referenced: CREATE TABLESPACE, CREATE LIBRARY, and CREATE DIRECTORY.


Remapping datafiles is useful when you move databases between platforms that have different file naming conventions. The source_datafile and target_datafile names should be exactly as you want them to appear in the SQL statements where they are referenced. Oracle recommends that you enclose datafile names in quotation marks to eliminate ambiguity on platforms for which a colon is a valid file specification character.

DIRECTORY=dpump_dir1 FULL=Y DUMPFILE=db_full.dmp

REMAP_SCHEMA: Default: none. Loads all objects from the source schema into a target schema.


Multiple REMAP_SCHEMA lines can be specified, but the source schema must be different for each one. However, different source schemas can map to the same target schema. The mapping may not be 100 percent complete, because there are certain schema references that Import is not capable of finding. For example, Import will not find schema references embedded within the body of definitions of types, views, procedures, and packages.

> expdp SYSTEM/password SCHEMAS=hr DIRECTORY=dpump_dir1 DUMPFILE=hr.dmp
> impdp SYSTEM/password DIRECTORY=dpump_dir1 DUMPFILE=hr.dmp REMAP_SCHEMA=hr:scott

In this example, if user scott already exists before the import, then the Import REMAP_SCHEMA command will add objects from the hr schema into the existing scott schema. You can connect to the scott schema after the import by using the existing password (without resetting it).

If user scott does not exist before you execute the import operation, Import automatically creates it with an unusable password. This is possible because the dump file, hr.dmp, was created by SYSTEM, which has the privileges necessary to create a dump file that contains the metadata needed to create a schema. However, you cannot connect to scott on completion of the import, unless you reset the password for scott on the target database after the import completes.


REMAP_TABLESPACE:  Default: none.  Remaps all objects selected for import with persistent data in the source tablespace to be created in the target tablespace.


Multiple REMAP_TABLESPACE parameters can be specified, but no two can have the same source tablespace. The target schema must have sufficient quota in the target tablespace.

> impdp hr/hr REMAP_TABLESPACE=tbs_1:tbs_6 DIRECTORY=dpump_dir1 DUMPFILE=employees.dmp 


REUSE_DATAFILES: Default: n. Specifies whether or not the import job should reuse existing datafiles for tablespace creation.


If the default (n) is used and the datafiles specified in CREATE TABLESPACE statements already exist, an error message from the failing CREATE TABLESPACE statement is issued, but the import job continues. If this parameter is specified as y, the existing datafiles are reinitialized. Be aware that specifying Y can result in a loss of data.

> impdp hr/hr DIRECTORY=dpump_dir1 DUMPFILE=expfull.dmp LOGFILE=reuse.log REUSE_DATAFILES=Y
There is a new parameter that allows you during export or import to modify the input or output data based on your remapping scheme. The  REMAP_DATA parameter specifies a remap function that takes as a source the original value of the designated column and returns a remapped value that will replace the original value in the  dump file. The syntax of the using the parameter is as follows:
expdp hr/passwd DIRECTORY=dp_dir DUMPFILE=remap.dmp
TABLES=hr.employees REMAP_DATA=hr.employees.last_name:hr.remap_pckg.modifychar



In Oracle 11g, the Data Pump allows you to rename a table  during the import process with the  REMAP_TABLE parameter. Syntax of this parameter is as follows:



Following are examples of using this parameter

impdp dumpfile=dp_dir:docs.dmp userid=hr/password

impdp dumpfile=dp_dir:docs.dmp userid=hr/password

Note Tables will not be remapped if they already exist even if the TABLE_EXISTS_ACTION  is set to




In Oracle 11g, setting the DATA_OPTIONS parameter to SKIP_CONSTRAINT_ERRORS will cause the import program  to skip errors generated by the nondeferred database constraints. In the case of deferred constraints, imports  will always be rolled back.

impdp Robert/robert DIRECTORY=data_pump_dir DUMPFILE=remap.dmp tables=ROBERT.NAMES  data_options=SKIP_CONSTRAINT_ERRORS


SCHEMAS: Default: none.  Specifies that a schema-mode import is to be performed.

SCHEMAS=schema_name [,...]

If you have the IMP_FULL_DATABASE role, you can use this parameter to perform a schema-mode import by specifying a list of schemas to import. First, the schemas themselves are created (if they do not already exist), including system and role grants, password history, and so on. Then all objects contained within the schemas are imported. Nonprivileged users can specify only their own schemas or schemas remapped to their own schemas. In that case, no information about the schema definition is imported, only the objects contained within it.

Schema-mode is the default mode when you are performing a network-based import.

> impdp hr/hr SCHEMAS=hr DIRECTORY=dpump_dir1 LOGFILE=schemas.log DUMPFILE=expdat.dmp


SKIP_UNUSABLE_INDEXES: Default: the value of the Oracle Database configuration parameter, SKIP_UNUSABLE_INDEXES. Specifies whether or not Import skips loading tables that have indexes that were set to the Index Unusable state (by either the system or the user).

SKIP_UNUSABLE_INDEXES={y | n} whose default value is Y

If SKIP_UNUSABLE_INDEXES is set to y, and a table or partition with an index in the Unusable state is encountered, the load of that table or partition proceeds anyway, as if the unusable index did not exist.

If SKIP_UNUSABLE_INDEXES is set to n, and a table or partition with an index in the Unusable state is encountered, that table or partition is not loaded. Other tables, with indexes not previously set Unusable, continue to be updated as rows are inserted.

Note: This parameter is useful only when importing data into an existing table. It has no practical effect when a table is created as part of an import because in that case, the table and indexes are newly created and will not be marked unusable.

> impdp hr/hr DIRECTORY=dpump_dir1 DUMPFILE=expfull.dmp LOGFILE=skip.log SKIP_UNUSABLE_INDEXES=y


SQLFILE: Default: none. Specifies a file into which all of the SQL DDL that Import would have executed, based on other parameters, is written.


The file_name specifies where the import job will write the DDL that would be executed during the job. The SQL is not actually executed, and the target system remains unchanged. The file is written to the directory object specified in the DIRECTORY parameter, unless another directory_object is explicitly specified here. Any existing file that has a name matching the one specified with this parameter is overwritten.

Note that passwords are not included in the SQL file. For example, if a CONNECT statement is part of the DDL that was executed, it will be replaced by a comment with only the schema name shown. In the following example, the dashes indicate that a comment follows, and the hr schema name is shown, but not the password.


Therefore, before you can execute the SQL file, you must edit it by removing the dashes indicating a comment and adding the password for the hr schema (in this case, the password is also hr), as follows:

> impdp hr/hr DIRECTORY=dpump_dir1 DUMPFILE=expfull.dmp

STATUS: Default: 0.

STREAMS_CONFIGURATION:  Default: y. Specifies whether or not to import any general Streams metadata that may be present in the export dump file.

> impdp hr/hr DIRECTORY=dpump_dir1 DUMPFILE=expfull.dmp STREAMS_CONFIGURATION=n


TABLE_EXISTS_ACTION: Default: SKIP (Note that if CONTENT=DATA_ONLY is specified, the default is APPEND, not SKIP.).  Tells Import what to do if the table it is trying to create already exists.


The possible values have the following effects:

  • SKIP leaves the table as is and moves on to the next object. This is not a valid option if the CONTENT parameter is set to DATA_ONLY.
  • APPEND loads rows from the source and leaves existing rows unchanged.
  • TRUNCATE deletes existing rows and then loads rows from the source.
  • REPLACE drops the existing table and then creates and loads it from the source. This is not a valid option if the CONTENT parameter is set to DATA_ONLY.

The following considerations apply when you are using these options:

  • When you use TRUNCATE or REPLACE, make sure that rows in the affected tables are not targets of any referential constraints.
  • When you use SKIP, APPEND, or TRUNCATE, existing table-dependent objects in the source, such as indexes, grants, triggers, and constraints, are ignored. For REPLACE, the dependent objects are dropped and re-created from the source, if they were not explicitly or implicitly excluded (using EXCLUDE) and they exist in the source dump file or system.
  • When you use APPEND or TRUNCATE, checks are made to ensure that rows from the source are compatible with the existing table prior to performing any action.
  • The existing table is loaded using the external tables access method if the existing tables have active constraints and triggers. However, be aware that if any row violates an active constraint, the load fails and no data is loaded. If you have data that must be loaded, but may cause constraint violations, consider disabling the constraints, loading the data, and then deleting the problem rows before reenabling the constraints.
  • When you use APPEND, the data is always loaded into new space; existing space, even if available, is not reused. For this reason, you may wish to compress your data after the load.

TRUNCATE cannot be used on clustered tables or over network links.

> impdp hr/hr TABLES=employees DIRECTORY=dpump_dir1 DUMPFILE=expfull.dmp TABLE_EXISTS_ACTION=REPLACE


TABLES:  Default: none.  Specifies that you want to perform a table-mode import.


TABLESPACES:  Default: none. Specifies that you want to perform a tablespace-mode import.


TRANSFORM: Default: none.  Enables you to alter object creation DDL for specific objects, as well as for all applicable objects being loaded.

TRANSFORM = transform_name:value[:object_type]

The transform_name specifies the name of the transform. The possible options are as follows:

  • SEGMENT_ATTRIBUTES - If the value is specified as y, then segment attributes (physical attributes, storage attributes, tablespaces, and logging) are included, with appropriate DDL. The default is y.
  • STORAGE - If the value is specified as y, the storage clauses are included, with appropriate DDL. The default is y. This parameter is ignored if SEGMENT_ATTRIBUTES=n.
  • OID - If the value is specified as n, the assignment of the exported OID during the creation of object tables and types is inhibited. Instead, a new OID is assigned. This can be useful for cloning schemas, but does not affect referenced objects. The default value is y.
  • PCTSPACE - The value supplied for this transform must be a number greater than zero. It represents the percentage multiplier used to alter extent allocations and the size of data files.

Note that you can use the PCTSPACE transform in conjunction with the Data Pump Export SAMPLE parameter so that the size of storage allocations matches the sampled data subset. The type of value specified depends on the transform used. Boolean values (y/n) are required for the SEGMENT_ATTRIBUTES, STORAGE, and OID transforms. Integer values are required for the PCTSPACE transform.

> impdp hr/hr TABLES=hr.employees \
  DIRECTORY=dpump_dir1 DUMPFILE=hr_emp.dmp \

TRANSPORT_DATAFILES: Default: none.  Specifies a list of datafiles to be imported into the target database by a transportable-mode import. The files must already have been copied from the source database system.


The datafile_name must include an absolute directory path specification (not a directory object name) that is valid on the system where the target database resides.

DIRECTORY=dpump_dir1 DUMPFILE=tts.dmp

TRANSPORT_FULL_CHECK: Default: n. Specifies whether or not to verify that the specified transportable tablespace set has no dependencies.


If TRANSPORT_FULL_CHECK=y, then Import verifies that there are no dependencies between those objects inside the transportable set and those outside the transportable set. The check addresses two-way dependencies. For example, if a table is inside the transportable set but its index is not, a failure is returned and the import operation is terminated. Similarly, a failure is also returned if an index is in the transportable set but the table is not.

If TRANSPORT_FULL_CHECK=n, then Import verifies only that there are no objects within the transportable set that are dependent on objects outside the transportable set. This check addresses a one-way dependency. For example, a table is not dependent on an index, but an index is dependent on a table, because an index without a table has no meaning. Therefore, if the transportable set contains a table, but not its index, then this check succeeds. However, if the transportable set contains an index, but not the table, the import operation is terminated.


TRANSPORT_TABLESPACES: Default: none. Specifies that you want to perform a transportable-tablespace-mode import.

TRANSPORT_TABLESPACES=tablespace_name [, ...]

Use the TRANSPORT_TABLESPACES parameter to specify a list of tablespace names for which object metadata will be imported from the source database into the target database.

DIRECTORY=dpump_dir1 NETWORK_LINK=source_database_link



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