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reading index file

Posted on 2013-06-04
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Last Modified: 2013-06-18
In my application, I see b-trees are populated in memory and is stored persistenty on file on the system also. How can I read this file, as I need to replace all the values of keys due to change in data structure of value
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Question by:perlperl
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3 Comments
 
LVL 84

Expert Comment

by:ozo
ID: 39219146
That depends on your application.
Does your application have a function to read the file?
Can you determine the file format your application uses to store  b-trees?
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Expert Comment

by:sarabande
ID: 39219488
if you have the store function you easily could deduce the read function from it (if not already exists as mentioned by ozo). in some cases the stored data was encrypted and needs decryption when read from file.

normally a stored b-tree would be read at initialization phase into memory. it is much likely that it has fixed-record length and binary data.

changing the keys will arise problems in a b-tree as the keys are sorted and (normally) are stored in packed format. so any change in length or value would make the tree invalid as long as you don't use the built-in remove and insert functions.

Sara
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Accepted Solution

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Minh Võ Công earned 1500 total points
ID: 39253330
This is a sample implementation B-tree in file

http://forum.codecall.net/topic/41058-b-tree-c-implementation/
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