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ResultSet - capacity?

 
Johann Evans
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Im not sure how the ResultSet class works - when you use a Statement to executeQuery(), does it execute the query to the database and then return the ENTIRE resulset into the ResultSet object, or does the ResultSet object "fetch" the record on call of the next() method?
 
Peter den Haan
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This is an implementation detail of the JDBC driver. Drivers will generally not try to read the entire result set in one go -- after all, result sets might be very large and you'd run out of memory. Most do not normally fetch one record at a time either -- the network overhead to the database server would be prohibitive. What most drivers do is download N records at a time, downloading new bunches as/when necessary. In many drivers, N is a configurable parameter. Think N = 30-100 records or so.
- Peter
[ January 13, 2003: Message edited by: Peter den Haan ]
 
Younes Essouabni
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With Oracle, the default fetch size is 32. But you may change it using the method setFetchsize(int). There is an interesting link about it. Look for the topic "Use Blocked fetch", a little bit after the middle of the page
 
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