I have a few questions regarding existing MySQL databases. If you have an already existing MySQL database, does TurboGears automatically create a module with the object classes for you? Or would you basically have to re-create everything in TurboGears? Also, if you decide later to change or delete a field in a table, would that change automatically be reflected in all the code automatically (like WebObjects does)? Or would you have to find all the code that references that table and make the adjustments yourself? What if you make changes through PHPMyAdmin? Does TurboGears recognize that something has changed?
Thank you. Tina Matter
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------------------------------------------------------- *Tina Matter* Web Software Developer Department of Mechanical Engineering University of Michigan 734-763-3184 -------------------------------------------------------
Tina Matter wrote: > I have a few questions regarding existing MySQL databases. > If you have an already existing MySQL database, does TurboGears > automatically create a module with the object classes for you? > Or would you basically have to re-create everything in TurboGears? > Also, if you decide later to change or delete a field in a table, would > that change automatically be reflected in all the code automatically > (like WebObjects does)? Or would you have to find all the code that > references that table and make the adjustments yourself? > What if you make changes through PHPMyAdmin? Does TurboGears recognize > that something has changed?
This is a helpful start. Thank you. However, if we decide to use TurboGears, we would need to use SQLAlchemy because we have an existing database that has multiple columns that represent primary keys in many of our tables. I was hoping that there would be a way to generate the python model code from an existing MySQL database, and then be able to update that model code automatically or through some program whenever changes are made to the database through something like PHPMyAdmin. It sounds like it would be more difficult to write code in TurboGears if the database is not represented in the python module.
Tina
On Jul 17, 1:40 pm, Jeff Miller <jeffmi...@gmail.com> wrote:
> Tina Matter wrote: > > I have a few questions regarding existing MySQL databases. > > If you have an already existing MySQL database, does TurboGears > > automatically create a module with the object classes for you? > > Or would you basically have to re-create everything in TurboGears? > > Also, if you decide later to change or delete a field in a table, would > > that change automatically be reflected in all the code automatically > > (like WebObjects does)? Or would you have to find all the code that > > references that table and make the adjustments yourself? > > What if you make changes through PHPMyAdmin? Does TurboGears recognize > > that something has changed?
On Tue, 2007-17-07 at 20:57 +0200, Christopher Arndt wrote: > tinab schrieb: > > I was hoping that there would be a way to generate the > > python model code from an existing MySQL database,
I just did this with SQLalchemy and it was surprisingly easy. You will probably want to go straight to the SA docs. All you need to do is make a stub class and then use assign_mapper to map your stub class to the existing table. You will probably also need to explicitly state the relationship keys, which can be found in the SA docs in the advanced data mapping section.
Here is an example from my project, please excuse the poor formatting:
# to load the table definition by introspecting the database heard_table = Table('how_heard', metadata, autoload=True) class Heard(object): pass assign_mapper(session.context, Heard, heard_table )
# to load the table definition by introspecting the database orders_table = Table('orders', metadata, autoload=True) class Orders(object): pass assign_mapper(session.context, Orders, orders_table )
locations_table = Table('locations', metadata, autoload=True) class Locations(object): # attribute for total number of boxes ordered by a location def _box_total(self): count = 0 for order in self.orders: if order.status == 'verified': count += order.quantity return count box_total = property( _box_total )
locations_dates_table = Table('locations_dates', metadata, autoload=True ) class LocationDates(object): pass
# because the old tables don't have foreign key defs, we need to explicitly state them here assign_mapper(session.context, Locations, locations_table, properties=dict( orders=relation(Orders, primaryjoin=and_( orders_table.c.location_id==locations_table.c.location_id ), foreignkey=orders_table.c.location_id ), champion=relation( Champions, primaryjoin=and_( locations_table.c.user_id==champions_table.c.user_id ), foreignkey=locations_table.c.user_id ), dates=relation( LocationDates, primaryjoin=and_( locations_table.c.location_id==locations_dates_table.c.location_id ), foreignkey=locations_dates_table.c.location_id, order_by=locations_dates_table.c.date ), ) )
iain duncan wrote: > On Tue, 2007-17-07 at 20:57 +0200, Christopher Arndt wrote: >> tinab schrieb: >>> I was hoping that there would be a way to generate the >>> python model code from an existing MySQL database,
> I just did this with SQLalchemy and it was surprisingly easy. You will > probably want to go straight to the SA docs. All you need to do is make > a stub class and then use assign_mapper to map your stub class to the > existing table. You will probably also need to explicitly state the > relationship keys, which can be found in the SA docs in the advanced > data mapping section.
> Here is an example from my project, please excuse the poor formatting:
> # to load the table definition by introspecting the database > heard_table = Table('how_heard', metadata, autoload=True) > class Heard(object): > pass > assign_mapper(session.context, Heard, heard_table )
> # to load the table definition by introspecting the database > orders_table = Table('orders', metadata, autoload=True) > class Orders(object): > pass > assign_mapper(session.context, Orders, orders_table )
> locations_table = Table('locations', metadata, autoload=True) > class Locations(object): > # attribute for total number of boxes ordered by a location > def _box_total(self): > count = 0 > for order in self.orders: > if order.status == 'verified': count += order.quantity > return count > box_total = property( _box_total )
> On Tue, 2007-17-07 at 20:57 +0200, Christopher Arndt wrote: > > tinab schrieb: > > > I was hoping that there would be a way to generate the > > > python model code from an existing MySQL database,
> I just did this with SQLalchemy and it was surprisingly easy. You will > probably want to go straight to the SA docs. All you need to do is make > a stub class and then use assign_mapper to map your stub class to the > existing table. You will probably also need to explicitly state the > relationship keys, which can be found in the SA docs in the advanced > data mapping section.
> Here is an example from my project, please excuse the poor formatting:
> # to load the table definition by introspecting the database > heard_table = Table('how_heard', metadata, autoload=True) > class Heard(object): > pass > assign_mapper(session.context, Heard, heard_table )
> # to load the table definition by introspecting the database > orders_table = Table('orders', metadata, autoload=True) > class Orders(object): > pass > assign_mapper(session.context, Orders, orders_table )
> locations_table = Table('locations', metadata, autoload=True) > class Locations(object): > # attribute for total number of boxes ordered by a location > def _box_total(self): > count = 0 > for order in self.orders: > if order.status == 'verified': count += order.quantity > return count > box_total = property( _box_total )
> and the addon AutoCode2 is tested with MySQL, it appears. > Paul
> iain duncan wrote: > > On Tue, 2007-17-07 at 20:57 +0200, Christopher Arndt wrote: > >> tinab schrieb: > >>> I was hoping that there would be a way to generate the > >>> python model code from an existing MySQL database,
> > I just did this with SQLalchemy and it was surprisingly easy. You will > > probably want to go straight to the SA docs. All you need to do is make > > a stub class and then use assign_mapper to map your stub class to the > > existing table. You will probably also need to explicitly state the > > relationship keys, which can be found in the SA docs in the advanced > > data mapping section.
> > Here is an example from my project, please excuse the poor formatting:
> > # to load the table definition by introspecting the database > > heard_table = Table('how_heard', metadata, autoload=True) > > class Heard(object): > > pass > > assign_mapper(session.context, Heard, heard_table )
