Re: [UrbanSim-Users] MySql configuration

Hi Philippe,

I'm not able to give you definitive answers, but:

> 1) Non-transactionnal database
> When prompted for the type of database usage, please choose
> 'Non-transactional Database Only' to configure the server to be compatible
> with UrbanSim. (The MyISAM format stores each table as a set of three files:
> a .frm, a .MYD, and a .MYI file. The InnoDB format does not use these
> files.) Press the 'Next' button.
>
> Is it possible to set the InnoDB transactionnal database ?
> Perhaps not, because not all data produced by Urbansim/Python programs are
> not explicitly commited to the database. For sample where launch a
> run_estimation.py the table land_price_model_coefficients was created but
> empty, in order to solve the problem we have add a "commit" statement at the
> end of the script.

You're right that our scripts don't commit things to the database.
However, we are currently in the midst of converting our database code
to use sqlalchemy (www.sqlalchemy.org), which allows us to interact with
any database engine (e.g. mysql, postgres...). Once we get that
conversion in place, all queries are autocommitted. So I anticipate that
in the next month or two transactional databases will be 100% supported.

>
> 2) Character Set
> On the following screen, make sure the 'Standard Character Set' option is
> selected and proceed by pressing the 'Next' button.
> (It makes the Latin1 the default character set)
>
> Can we use the UTF8 character set ? In our experiences for loading new data
> in MySql database from external files (LOAD DATA instruction) it fails using
> the Latin1 character and table successfully loaded if the table set with
> UTF8 character set.

I don't see why using utf8 encoding would make anything fail. It would
be very helpful if you could try it out and let us know how it works.
Unfortunately, I have seen some strange and unintuitive errors emerge
from incompatibilities between character sets.

>
> In MySql, is it possible (by a setting) to force the Decimal separator (ie:
> International = "." French = ",") to match the file data to load in MySql ?
>
> In Windows MySql use the regional setting to determine the Decimal separator
> and an error appears if it not match the file data.

I'm sorry, I don't follow the question. It sounds like something that
might better be answered over the mysql forums: http://forums.mysql.com/.

Cheers,
Travis
Received on Mon Sep 17 2007 - 10:53:27 PDT