executemany() syntax is very efficient and I dont really understand
how the column/string thing is that much of an issue other than an
small inconvenience and a slight failure of the API to be
consistent...all you have to do is convert the dict keys to be
column.key.
On Nov 26, 2008, at 5:52 PM, MikeCo wrote:
>
> Oops, I stand corrected. see http://pastebin.com/fe4a38d6
>
> At least for SQLite, my loop solution is many times slower than the
> insert many syntax. I would be curious to see results run against
> different database engines. I don't have quick access to them right
> now.
> Still, unless there are very large numbers of inserts there should be
> little, if any, noticeable difference.
>
> --
> Mike
>
>
> On Nov 26, 4:50 pm, MikeCo <[EMAIL PROTECTED]> wrote:
>> You probably don't want to do the inserts one by one because of the
>> commit overhead, or needing to rollback on failure of on insert. You
>> can still get multiple inserts in one transaction. Add this to the
>> example posted athttp://pastebin.com/fd0653b0to see three inserts in
>> one transaction.
>>
>> print '****', '5. column attributes in .values()'
>> data = [{MyTable.c.col1:itm.x} for itm in items]
>> print '****', data
>> trans = conn.begin() # < - - start a transaction to wrap many
>> inserts
>> for d in data:
>> conn.execute(MyTable.insert().values(d))
>> trans.commit() # < - - end transaction
>>
>> Wrapping the insert loop in a transaction should give you the same or
>> very nearly the same performance as executing the "insert many"
>> operation, and only adds 4 or 5 simple lines of code. The exception
>> might be if you have a large batch process inserting thousands or
>> tens
>> of thousands of records; in that case, you will need to design a
>> solid
>> commit strategy anyway. with or without SQLAlchemy.
>>
>> --
>> Mike
>>
>> On Nov 26, 10:42 am, "Michael Bayer" <[EMAIL PROTECTED]>
>> wrote:
>>
>>> Petr Kobalíèek wrote:
>>
>>>> So, I can use that way in inserting one row, but can't when
>>>> inserting
>>>> multiple rows ? It is correct ?
>>
>>> you can only use string keys as the arguments to the execute()
>>> method.
>>> this applies to one row or many. columns as keys can be used for
>>> the
>>> values argument/generative method on an insert() or update()
>>> construct.
>>
>>> to be quite honest there was never an intention for columns as
>>> keys to not
>>> work properly when sent as keys as parameters to .execute(), there
>>> just
>>> seems to be a lack of testing in this case, so feel free to file a
>>> ticket
>>> for this.
> >
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