On Wed, Nov 7, 2018 at 7:34 PM Luke <[email protected]> wrote:
>
> Michael and others:
>
> My goal is to have an orm Mixin that implements everything for Postgresql
> tsvector full-text search
> that I can import as a single object into a new project.
>
> I haven't been able to get a event.listen( ... trigger DDL ...) to work as
> part of a Mixin. I don't really
> understand the docs on __declare_last__, so I'm working from some
> stackoverflow answers. The code
> creates the expected Index and Trigger if the statements are defined outside
> of the class.
>
> ```
> class Searchable:
> """ An SQLAlchemy ORM Mixin that creates Postgres TSVECTOR columns
>
> :example:
> >>> class Text(Searchable, Base):
> >>> pass
>
> """
>
> # Original inspiration:
> http://shisaa.jp/postset/postgresql-full-text-search-part-1.html
>
> # __abstract__ = True
>
> _trigger_ddl = DDL(
> "create trigger ts_update before insert or update on text for "
> "each row execute procedure tsvector_update_trigger(tsvector, "
> "'pg_catalog.english', 'text');"
> )
>
> # Data Fields
> text = Column(String)
>
> # PostgreSQL Full Text Search field
> # http://www.postgresql.org/docs/current/static/datatype-textsearch.html
> tsvector = Column(postgresql.TSVECTOR)
>
> @declared_attr
> def __table_args__(cls):
> # CREATE INDEX tsvector_idx ON tsvector USING
> gin(to_tsvector('english', message));
> # Note: __table_args__ should return a tuple
> return (Index(
> "tsvector_idx_%s" % cls.__tablename__,
> "tsvector",
> postgresql_using="gin",
> ),)
>
> @classmethod
> def __declare_last__(cls):
> event.listen(
> cls,
> "after_create",
> cls._trigger_ddl.execute_if(dialect="postgresql"),
> )
> ```
ignore my previous email, this event handler should be failing,
there's no after_create event for a mapped class. you'd want to
put this on the Table for which the class is mapped. You don't need
to use __declare_last__ as the Table can take these within the
arguments:
class MyClass:
@declared_attr
def __table_args__(cls):
return (Index(...), {"listeners": [("after_create", my_create_event)]})
>
> When __abstract__ = True the subclass is unmapped and no ddl is emitted on
> create_all(). I did not expect that.
>
> Is it possible to have the Mixin execute the event.listen or otherwise
> created the trigger?
>
> Thanks,
> Luke
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
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--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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