Takusen - reading from one db inserting into another
Hi, I know how to use Takusen with a *single* connection, but I cannot figure out how to read from one database while inserting to another. Could someone please explain to me how I can do that? Günther
Don't know if you can have two connections, sounds difficult in regard to the DBM monad. Only the deveolopers will know. However, two obvious solutions come to my mind: 1) build a result set and process it after returning from DBM or 2) use two separate threads and send the queried data from your source db to the other thread using an STM channel. You will have to think about lazyness, performance and space usage in both cases, however. Am Sonntag, den 17.01.2010, 20:48 +0100 schrieb Günther Schmidt:
Hi,
I know how to use Takusen with a *single* connection, but I cannot figure out how to read from one database while inserting to another.
Could someone please explain to me how I can do that?
Günther
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Hello Günther,
I know how to use Takusen with a *single* connection, but I cannot figure out how to read from one database while inserting to another.
At present it's not possible. The lats time you asked about it, Oleg and I tried a design where the DBM monad becomes a DBMT monad transformer. This permits multiple connections, but the resulting user-land code didn't work as well as I wanted. If you like I can try to tidy it up and send you the darcs patch. Alistair
Hello Alistair, sorry for asking twice, I had forgotten that. I took some time to try to figure out how to do it and always concluded from my understanding of Takusen that it shouldn't be possible. At least it seems I got that right, which is good by itself :) . Thank you for your troubles but do not worry about the patch, I have switched back to using HDBC meanwhile. HDBC-ODBC has a slight problem with Access, I couldn't insert Doubles, well I could but the decimal separator got swallowed, and I worked around it by using pr-efilled SQL-statement strings instead of bound/prepared ones. Günther Am 18.01.10 13:00, schrieb Alistair Bayley:
Hello Günther,
I know how to use Takusen with a *single* connection, but I cannot figure out how to read from one database while inserting to another.
At present it's not possible. The lats time you asked about it, Oleg and I tried a design where the DBM monad becomes a DBMT monad transformer. This permits multiple connections, but the resulting user-land code didn't work as well as I wanted. If you like I can try to tidy it up and send you the darcs patch.
Alistair
participants (3)
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Alistair Bayley -
Günther Schmidt -
Michael Hartl