On Tuesday, October 9, 2012 11:32:18 AM UTC-7, Tassilo Horn wrote: > > Brian Craft <craft...@gmail.com <javascript:>> writes: > > > How would I do an operation involving two databases? I'd need to call > > with-connection* from with-connection*? How would I then read from one > > & write to the other? > > I've never used the jdbc lib, but essentially it should be something > along the lines of > > (let [db1 (connect-to-db1) > db2 (connect-to-db2)] > (with-connection* db2 > (write-stuff (with-connection* db1 (read-stuff))))) > > If (read-stuff) is not lazy, then this looks pretty simple: all the data is loaded in memory & returned to (write-stuff). If the data is large you wouldn't want it all in memory. What then? Could you make read-stuff return a lazy sequence? My impression after a brief experiment is that this doesn't work: when the inner with-connection* returns, the db connection is closed. A lazy sequence from (read-stuff) then can't be evaluated w/o throwing an error.
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