SQLAlchemy is broadly separated into 2 parts, "core" and "ORM" (which you can
see as the left and right-hand sides on the front page of the documentation,
http://docs.sqlalchemy.org/en/rel_0_8/)
Table objects like the one you have below are part of the Core API. Columns of
Table objects are accessible via the "c" property:
process_files.c.process_id
The ORM is built on top of the core API. When you do something like:
class Files(Base):
__tablename__ = 'files'
id = sa.Column('id', sa.Integer, primary_key=True)
…you are creating a "mapped class". You can access the columns of these
directly like "Files.id". If you ever need access to the underlying Table
object, you can get it from Files.__table__.
When using things like session.query(), you can often use tables or mapped
classes interchangeably.
Hope that helps,
Simon
On 7 Mar 2013, at 20:57, Mauricio de Abreu Antunes <mauricio.abr...@gmail.com>
wrote:
> Simon,
>
> Here is the table (not sure if the code to create a relationship table is
> correct):
>
>
> # Many to Many - Process x Files
>
>
>
> process_files = Table("process_files", Base.metadata,
>
>
>
> Column("process_id", Integer, ForeignKey("process.id")),
>
>
>
> Column("files_id", Integer, ForeignKey("files.id"))
>
>
>
> )
>
>
>
>
> The error:
>
> AttributeError: 'Table' object has no attribute 'process_id'
>
>
> Why can not I access process_id?
>
> 2013/3/7 Simon King <si...@simonking.org.uk>
> The ORM tutorial covers querying with joins:
>
> http://docs.sqlalchemy.org/en/rel_0_8/orm/tutorial.html#querying-with-joins
>
> In this case, you probably want something like this (if ProcessFiles is a
> class mapped to the process_files table):
>
> result =
> session.query(Files).join(ProcessFiles).filter(ProcessFiles.process_id==1)
>
> Hope that helps,
>
> Simon
>
> On 7 Mar 2013, at 20:35, Mauricio de Abreu Antunes
> <mauricio.abr...@gmail.com> wrote:
>
> > I wanna perform a query on process_files and hereafter a update/join like
> > this:
> >
> > SELECT files.id AS files_id, files.name AS files_name, files.directory AS
> > files_directory, files.active AS files_active, files.connection_id AS
> > files_connection_id
> > FROM files JOIN process_files ON files.id = process_files.files_id
> >
> > Actually the piece os select above is a result from:
> >
> > result = session.query(Files).join(process_files)
> >
> > It is ok, but i wanna filter it with process_files.process_id = 1 for
> > example.
> >
> > Reading the docs i could not find the proper way to do this:
> > http://docs.sqlalchemy.org/en/rel_0_7/orm/query.html#sqlalchemy.orm.query.Query.join
> >
> > Am i reading the wrong part of the docs?
> >
> > 2013/3/7 Mauricio de Abreu Antunes <mauricio.abr...@gmail.com>
> > These tips are veeery good!
> > I sometimes get lost about the best way to use the best ORM library in the
> > world.
> >
> >
> > 2013/3/7 Simon King <si...@simonking.org.uk>
> > This is an unusual way to update an object that you've already retrieved:
> >
> > result = session.query(Executions). \
> > filter_by(id=execution_id).first()
> > if result.end_date is None:
> > e =
> > update(Executions).where(Executions.id==bindparam("execution_id")). \
> > values(end_date=bindparam("now"))
> > self.connection.execute(e, execution_id=execution_id,
> > now=datetime.datetime.now())
> >
> > It would be more natural to write it like this:
> >
> > if result.end_date is None:
> > result.end_date = datetime.datetime.now()
> > session.flush()
> >
> > Also, if "id" is the primary key on your Executions class, you can
> > write the first line as:
> >
> > result = session.query(Executions).get(execution_id)
> >
> >
> > On Thu, Mar 7, 2013 at 1:58 AM, Michael Bayer <mike...@zzzcomputing.com>
> > wrote:
> > > in the 0.7 series, you can't pass an ORM mapped class as the subject of
> > > the
> > > core update() construct:
> > >
> > > e = update(Executions).where(Executions.id==bindparam("execution_id")). \
> > > values(end_date=bindparam("now"))
> > >
> > > that statement will work as is if you just refer to the Table:
> > >
> > > e =
> > > update(Executions.__table__).where(Executions.id==bindparam("execution_id")).
> > > \
> > > values(end_date=bindparam("now"))
> > >
> > > also note that the indirection between bindparam("foo") and
> > > connection.execute(stmt, foo="some value") is not needed; you can embed
> > > literal values directly in the statement, and the Core will convert them
> > > to
> > > bound parameters (just use echo=True to see it in action):
> > >
> > > e = update(Executions).where(Executions.id==execution_id). \
> > > values(end_date=datetime.datetime.now())
> > >
> > > At the ORM level, you can use query.update():
> > >
> > > session.query(Executions).filter(Executions.id==execution_id).update({"end_date":datetime.now()},
> > > synchronize_session=False)
> > >
> > >
> > > On Mar 6, 2013, at 8:06 PM, Mauricio de Abreu Antunes
> > > <mauricio.abr...@gmail.com> wrote:
> > >
> > > So, i have read @StackOverflow some tips.
> > > There is a lot of people saying they have to make a query on the table and
> > > then update it. there is no way to upgrade without performing a query?!
> > >
> > > On Wednesday, March 6, 2013 6:17:35 PM UTC-3, Mauricio de Abreu Antunes
> > > wrote:
> > >>
> > >> Hello,
> > >>
> > >> I'm new to SQLAlchemy. Currently I'm using SQLAlchemy 0.7.1.
> > >> Reading the tutorial, I tried to write my codes like those examples but I
> > >> had no success working on it.
> > >>
> > >> Code is here:
> > >> https://gist.github.com/mauricioabreu/5103163
> > >>
> > >> Do I need to map the table Executions to execute an update expression on
> > >> it?
> > >>
> > >> Sorry if this is a very noob question.
> > >>
> > >> If you need more info about the problem let me know.
> > >
> > >
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> > --
> > Mauricio de Abreu Antunes
> > Mobile: (51)930-74-525
> > Skype: mauricio.abreua
> >
> >
> >
> > --
> > Mauricio de Abreu Antunes
> > Mobile: (51)930-74-525
> > Skype: mauricio.abreua
> >
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> Mobile: (51)930-74-525
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>
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