Question

我从事Postgres的工作，并从SQL Alchemy开始。我创建了“ layout_api.py”

layout_api.py

from sqlalchemy import create_engine
from sqlalchemy import Column, String, Integer, TIMESTAMP, Sequence, text, types
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
import datetime, uuid


db_string = "postgres://postgres:password@10.***.**.**/gridcustomization"

Base = declarative_base()
db = create_engine(db_string) 


class Layout(Base):
    __tablename__ = "col.layout"
    layout_id = Column(UUID(as_uuid=True), nullable=False, primary_key=True)
    name = Column(String(1000), nullable=False)
    user_id = Column(UUID(as_uuid=True), nullable=False)
    ispublic = Column(Integer, default=0, nullable=False)
    isactive = Column(Integer, default=0, nullable=False)
    createdby = Column(Integer, default=1, nullable=False)

现在我只需要特定的列。与在SQL中一样，我们编写：

SELECT layout_id, user_id, isactive FROM col.layout;

我在SQL Alchemy中尝试了相同的方法，但是没有得到输出。

fetch_columns_data.py

class DBFetch:

    def get(self):
        Session = sessionmaker(bind=db)   #make session to query data
        session = Session()
        Base.metadata.create_all(db)
        session.query("SET search_path TO col")

        result = []
        selected_columns = Layout.__table__.columns   # specific columns selected by user
        print("Selected columns {}".format(selected_columns))
        record = session.query(Layout).with_entities(*selected_columns).one()
        for row in record:
            result.append((row._asdict()))
        print(result)

如何从数据库中获取特定的列数据？我正在为仅需要特定列数据的用户尝试此操作。给我建议。预先感谢。

如何在SQL Alchemy中从Postgres数据库获取特定列数据

0 个答案: