今天就跟大家聊聊有关如何理解impdp transform参数，可能很多人都不太了解，为了让大家更加了解，小编给大家总结了以下内容，希望大家根据这篇文章可以有所收获。

使用实例

impdp hr TABLES=hr.employees DIRECTORY=dpump_dir1 DUMPFILE=hr_emp.dmp TRANSFORM=STORAGE:n:table
impdp hr DIRECTORY=dpump_dir1 DUMPFILE=hr.dmp SCHEMAS=hr TRANSFORM=SEGMENT_ATTRIBUTES:n

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TRANSFORM

Default: There is no default

Purpose

Enables you to alter object creation DDL for objects being imported.

Syntax and Description

TRANSFORM=transform_name:value[:object_type]

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

SEGMENT_ATTRIBUTES- If the value is specified asy, then segment attributes (physical attributes, storage attributes, tablespaces, and logging) are included, with appropriate DDL. The default isy.

STORAGE- If the value is specified asy, then the storage clauses are included, with appropriate DDL. The default isy. This parameter is ignored ifSEGMENT_ATTRIBUTES=n.

OID- If the value is specified asn, then 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 isy.

PCTSPACE- Thevaluesupplied 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 thePCTSPACEtransform with the Data Pump ExportSAMPLEparameter so that the size of storage allocations matches the sampled data subset. (See"SAMPLE".)

SEGMENT_CREATION- If set toy(the default), then this transform causes the SQLSEGMENT CREATIONclause to be added to theCREATE TABLEstatement. That is, theCREATE TABLEstatement will explicitly say eitherSEGMENT CREATION DEFERREDorSEGMENT CREATION IMMEDIATE. If the value isn, then theSEGMENT CREATIONclause is omitted from theCREATE TABLEstatement. Set this parameter tonto use the default segment creation attributes for the table(s) being loaded. (This functionality is available starting with Oracle Database 11grelease 2 (11.2.0.2).)

The type ofvaluespecified depends on the transform used. Boolean values (y/n) are required for theSEGMENT_ATTRIBUTES,STORAGE, andOIDtransforms. Integer values are required for thePCTSPACEtransform.

Theobject_typeis optional. If supplied, it designates the object type to which the transform will be applied. If no object type is specified, then the transform applies to all valid object types. The valid object types for each transform are shown inTable 3-1.

Table 3-1 Valid Object Types For the Data Pump Import TRANSFORM Parameter

CLUSTER

X

X

X

CONSTRAINT

X

X

X

INC_TYPE

X

INDEX

X

X

X

ROLLBACK_SEGMENT

X

X

X

TABLE

X

X

X

X

X

TABLESPACE

X

X

TYPE

X

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