我正在使用flask,sqlalchemy和flask-sqlalchemy。我想使用gin和to_tsvector在postgres中创建一个完整的测试搜索索引。目前,我正在尝试以下内容。我认为这是我接近表达目标的方式,但它不起作用。
from sqlalchemy.ext.declarative import declared_attr
from sqlalchemy.schema import Index
from sqlalchemy.sql.expression import func
from app import db
class Post(db.Model):
id = db.Column(db.Integer, primary_key=True)
added = db.Column(db.DateTime, nullable=False)
pub_date = db.Column(db.DateTime, nullable=True)
content = db.Column(db.Text)
@declared_attr
def __table_args__(cls):
return (Index('idx_content', func.to_tsvector("english", "content"), postgresql_using="gin"), )
这会抛出以下错误...
Traceback (most recent call last):
File "./manage.py", line 5, in <module>
from app import app, db
File "/vagrant/app/__init__.py", line 36, in <module>
from pep.models import *
File "/vagrant/pep/models.py", line 8, in <module>
class Post(db.Model):
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/flask_sqlalchemy.py", line 477, in __init__
DeclarativeMeta.__init__(self, name, bases, d)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/ext/declarative/api.py", line 48, in __init__
_as_declarative(cls, classname, cls.__dict__)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/ext/declarative/base.py", line 222, in _as_declarative
**table_kw)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/schema.py", line 326, in __new__
table._init(name, metadata, *args, **kw)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/schema.py", line 393, in _init
self._init_items(*args)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/schema.py", line 63, in _init_items
item._set_parent_with_dispatch(self)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/events.py", line 235, in _set_parent_with_dispatch
self._set_parent(parent)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/schema.py", line 2321, in _set_parent
ColumnCollectionMixin._set_parent(self, table)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/schema.py", line 1978, in _set_parent
self.columns.add(col)
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/sql/expression.py", line 2391, in add
self[column.key] = column
File "/home/vagrant/.virtualenvs/pep/local/lib/python2.7/site-packages/sqlalchemy/sql/expression.py", line 2211, in __getattr__
key)
AttributeError: Neither 'Function' object nor 'Comparator' object has an attribute 'key'
我也尝试过
return (Index('idx_content', "content", postgresql_using="gin"), )
然而,它不能像postgres一样工作(至少是9.1版本,因为我运行的是这个版本),因为它期望调用to_tsvector函数。这行代码生成SQL语句;
CREATE INDEX content_index ON post USING gin (content)
与其说是我想要的,
CREATE INDEX content_index ON post USING gin(to_tsvector('english', content))
我打开了一张工单,因为我认为这可能是一个错误/限制。http://www.sqlalchemy.org/trac/ticket/2605
column.key
дёЋcolumn.name
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