Python SQLAlchemy:映射PostGIS geom字段

Question

SQLAlchemy将DB列映射到Python中的对象成员.例如:

class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, Sequence('user_id_seq'), primary_key=True)
    name = Column(String(50))
    fullname = Column(String(50))
    password = Column(String(12))

应该使用哪种类型将PostGIS geom列映射到类成员？

Answer 1

据我所知,使用SQLAlchemy没有内置的方法.但是,GeoAlchemy2是SQLAlchemy的扩展,它增加了对地理空间字段(点,线,多边形等)的支持:

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, Sequence
from geoalchemy2 import Geometry

Base = declarative_base()

class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, Sequence('user_id_seq'), primary_key=True)
    name = Column(String(50))
    fullname = Column(String(50))
    password = Column(String(12))
    geom = Column(Geometry('POINT'))

GeoAlchemy2还提供空间查询功能.来自文档:

query = session.query(Lake).filter(Lake.geom.ST_Contains('POINT(4 1)'))