Python-PostgreSQL主键自动填充报错：SAWarning: Column x is marked as a member of the primary key for table x', but has no Python-side or server-side default generator indicated...

import datetime
from sqlalchemy import Column, String, inspect, Integer
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from sqlalchemy import create_engine

engine = create_engine(DATABASE_URL)
Base = declarative_base()
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

class Post(Base):
    __tablename__ = "post"
    id = Column(UUID, primary_key=True, index=True, autoincrement=False)
    time = Column(String)
    title = Column(String)
    content = Column(String)
    username = Column(String)

def create_post(post: dict) -> bool:
    db = SessionLocal()
    try:
        post = Post(data=post)
        db.add(post)
        db.commit()
        return True
    finally:
        db.close()

time = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
create_post({"title": "test", "content": "test", "username": "admin", 'time': time})

测试数据库接口是否正常时发生报错：

SAWarning: Column 'post.id' is marked as a member of the primary key for table 'post', but has no Python-side or server-side default generator indicated, nor does it indicate 'autoincrement=True' or 'nullable=True', and no explicit value is passed.  Primary key columns typically may not store NULL.

在PostgreSQL内，

• Primary key = id，
• Data type = uuid,
• Deafult = gen_random_uuid()，

并且数据类里也设置了 autoincrement=False，还是发生报错。经过尝试，发现：即使设置了默认填充的id，还是需要在后端这里指定：

id = Column(UUID(), primary_key=True, server_default=text("uuid_generate_v4()"))

顺利解决！

运行环境

PostgreSQL 16.2, compiled by Visual C++ build 1937, 64-bit

sqlalchemy~=2.0.30