hello, looking at the do_jdbc I see following advantages in using jdbc prepared statements: * escaping of parameters is done by the jdbc driver, i.e. no DB dependent code needed * the jdbc implementation can use DB side prepared statements (if the DB and jdbc driver supports it) * prepared statement pooling is available on a per connection base (if the driver supports it) * prepared statement pooling is available on connection pools if the connection comes from datasource which implements such pooling
the last three points depends on the jdbc driver and/or database. in case the database does not have DB side prepared statements than the driver process the sql string and the bind_values similar as DO is doing right now. a downside would be that there are jdbc driver/database combination where there is slight overhead using the jdbc prepared statements. for the last point above do_jdbc needs to be able to use a datasource for retrieving connections, i.e. use JNDI to retrieve the datasource. since typical j2ee datasources are pooled datasources, the DO pooling must be disabled/avoided. any objections against using jdbc prepared statements in do_jdbc ?? Kristian On Dec 2, 12:14 am, Dirkjan Bussink <[EMAIL PROTECTED]> wrote: > On 1 Dec 2008, at 18:22, Bernerd Schaefer wrote: > > > Now, that's necessary for some databases, but, of course, many support > > the preparing and binding DB side -- which is obviously much better. > > It's not always better, although we probably should use the driver's > parameter binding if we can. This could be done for example for MySQL > and PostgreSQL, which support binding parameters in the driver. This > can also improve the execution planning for the query, although that > really starts to matter with RDBMS's like Oracle. > > Always using prepared statements does incur an overhead, so that > should be done with care only. > > > DO also does not currently have any form of add/executeBatch, which, > > in conjunction with true prepared statements, would be really useful. > > Well, you'd probably want a LRU cache or something similar to maintain > the prepared statements that are used, so you don't create to much but > also not too little, so you can benefit from reusing inserts / updates. > > -- > Regards, > > Dirkjan Bussink --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "DataMapper" group. To post to this group, send email to datamapper@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/datamapper?hl=en -~----------~----~----~----~------~----~------~--~---
