| Export / Import [message #243738] |
Fri, 08 June 2007 12:42  |
rsreddy28
Messages: 295
Registered: May 2007
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Senior Member |
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Hello,
I've a small doubt..
when we have full database export and the next day say if we are going for an incremental export , how does Oracle identify which tables need to be exported . I've read the article in Oracle but I did'nt understand that.
Can somebody plz throw light on this.
And also all about the incremental , cumulative and complete export , I mean the role of Oracle internlly.
Bye,
Raj
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| Re: Export / Import [message #243739 is a reply to message #243738] |
Fri, 08 June 2007 12:45  |
DreamzZ
Messages: 1666
Registered: May 2007
Location: Dreamzland
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Senior Member |
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Complete
In order to use the complete parameter, the user must be able to do a full database export (FULL=Y). A full database export will export all the database objects so that database can be recreated from the ground up. The full database export will act as the starting point for a complete import. You must already have a complete export for the incremental and cumulative exports to be of any value because you import them after you import the complete.
Incremental
Incremental exports are where you can save time by only exporting the changed tables in the database. Most databases have tables that change slowly or never at all. If your database is fairly stable, you should consider using the incremental exports. These exports are usually faster than complete exports and consume less space. The export only has tables in it that have changed since the last incremental export, or if no other incremental exports exist, it exports tables that have changed since the last cumulative export. Lastly, Export looks for tables that have changed since the last complete export if a cumulative export does not exist. To use the incremental exports, you import them after the complete and cumulative exports are finished.
Cumulative
A cumulative export, in a sense, makes all of the incremental exports unnecessary. The cumulative export will export all the tables since the last complete export, including all the tables currently exported in the incremental exports. You do not need the incremental exports once a cumulative is completed.
http://www.webbasedprogramming.com/Oracle-Unleashed/oun09fi.htm#I18
and also see
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:832427034486
[Updated on: Fri, 08 June 2007 12:51] Report message to a moderator |
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| Re: Export / Import [message #243740 is a reply to message #243739] |
Fri, 08 June 2007 12:54 |
rsreddy28
Messages: 295
Registered: May 2007
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Senior Member |
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Hi,
But my doubt is :
How does Oracle know which tables need to be backed up since the last full database export.
How does Oracle internally know what need to backed up since the last backup????
Hope my question is clear . I was asked this question in an interview.
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