begin/commit's in DBAPI have no "statements" since there is really no
"begin", and "commit" is an API level call.
also, all DBAPI connections have autocommit turned off by default.
however, the engine is issuing an explicit "commit" call at the end
of every execution, if you dont have a transaction in progress, so it
has the effect of autocommit.
engine.begin() and engine.commit() will create a transaction and
bypass the auto-committing behavior. im not exactly sure how that
would "speed up" sqlite interaction? multiple writers with SQLite is
going to be a slow performer with autocommit or not.
On Apr 17, 2006, at 2:32 AM, Michael Gechter wrote:
Sorry of this is a repost -- I sent it once before joining the
list. I don't think it went through though...
---
Hello,
I've started using sqlalchemy a few weeks ago for a recent project.
Right now I've version locked to 0.1.5 unless there's a compelling
reason for me to move past that.
The database engine I'm using is sqlite. I haven't used sqlite
before, so I don't know how much of my question is sqlite versus SA
specific. Basically, I don't know how to start database
transactions with autocommit turned off. I only found a couple of
references to autocommit in the docs, but it didn't really suggest
how to turn autocommit off. (do i pass this in to the create_engine
function?)
As for the transactions themselves, engine.begin() should start one
and engine.commit() should commit that transaction to the database.
Is there a way to see these begin/commit/end statements echoed? I
see the inserts, deletes, updates and creates just fine, but no
transaction stuff.
As for why I want to use the db's transaction as opposed to the
unit of work: My file-based sqlite database interaction is going
very slow. I think this has to do with the fsync() call that sqlite
makes. The benchmark sites suggest using transactions for all
statements. Another option I'd be happy to is use the nosync option
referred to by the benchmark sites, but I couldn't find any mention
of that in the pysqlite2 source or documentation.
Sorry if this is too sqlite-centric but I was having trouble
separating the interaction of the two in my mind.
-Michael Gechter
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