Data access methods using data pump utility
Data access methods using data pump utility
A Data Pump export and import job can access the table data in either of the two ways:
Direct-Path :
This access uses the Direct Path API
Direct-path exports and imports lead to improved performance, since the direct path internal stream format is the same as the format stored in Oracle dump files. This leads to reduced need for data conversion
Oracle always uses direct-path method to load or unload data except under some conditions:
1) Clustered tables
2) Active triggers in tables
3) A single partition in a table with a global index
4) Referrential integrity constraints
5) Domain indexes on LOB columns
6) Tables with fine-grained access control enabled in the insert mode
7) Tables with BFILE or opaque type columns
It is mandatory to use direct-path access methods under the following conditions :
Table has any LONG data
External-tables :
This feature lets oracle read data from and write data to operating system files that lie outside the database.
Direct-path doesn’t support intra-partition parallelism and it is imperative to use external tables in such cases.
Under following conditions only external tables can be used :
1) Clustered tables
2) Active triggers in tables
3) A single partition in a table with a global index
4) Referrential integrity constraints
5) Domain indexes on LOB columns
6) Tables with fine-grained access control enabled in the insert mode
7) Tables with BFILE or opaque type columns
Note :
The data file format is identical in direct-path access method and external tables. So we can easily export data with one method and import data with other method.
-
Archives
- February 2017 (1)
- November 2016 (1)
- October 2016 (1)
- May 2016 (2)
- March 2016 (3)
- December 2014 (2)
- July 2014 (1)
- June 2014 (6)
- May 2014 (5)
- February 2014 (1)
- December 2012 (2)
- November 2012 (8)
-
Categories
-
RSS
Entries RSS
Comments RSS