DateTime Column is not coded properly

[John-Male]

Hi

This page has the following code for the ORM

https://www.pythonsheets.com/notes/python-sqlalchemy.html

class TestTable(Base): __tablename__ = 'Test Table' id = Column(Integer, primary_key=True) key = Column(String, nullable=False) val = Column(String) date = Column(DateTime, default=datetime.utcnow)

The proper way to code the DateTime column is

class TestTable(Base): __tablename__ = 'Test Table' id = Column(Integer, primary_key=True) key = Column(String, nullable=False) val = Column(String) date = Column(DateTime(), default=datetime.utcnow)
If you use the code from your example and have two DateTime columns coded this way then SQLalchemy will raise this error on the second column. sqlalchemy.exc.ArgumentError: Column must be constructed with a non-blank name or assign a non-blank .name before adding to a Table.

[crazyguitar]

@John-Male

Could you provide an example for me?

I try this

from datetime import datetime

from sqlalchemy import create_engine
from sqlalchemy import Column, Integer, String, DateTime
from sqlalchemy.orm import sessionmaker
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.engine.url import URL

engine = create_engine('sqlite://')

Base = declarative_base()

class TestTable(Base):
    __tablename__ = 'Test Table'
    id   = Column(Integer, primary_key=True)
    key  = Column(String, nullable=False)
    val  = Column(String)
    ctime = Column(DateTime, default=datetime.utcnow)
    mtime = Column(DateTime)


# create tables
Base.metadata.create_all(bind=engine)

# create session
Session = sessionmaker()
Session.configure(bind=engine)
session = Session()

data = {'a': 5566, 'b': 9527, 'c': 183}
try:
    for _key, _val in data.items():
        row = TestTable(key=_key, val=_val)
        session.add(row)
    session.commit()
except SQLAlchemyError as e:
    print(e)
finally:
    session.close()

but there is no sqlalchemy.exc.ArgumentError.

[John-Male]

Hi Here is a link to the code that was causing the error. I had opened an issue on the SQLAlchemy GITHUB site.  sqlalchemy/sqlalchemy#4692 I was connecting to a MYSQL database.  On Sunday, May 26, 2019, 11:57:00 PM PDT, chang-ning <notifications@github.com> wrote: @John-Male Could you provide an example for me? I try this from datetime import datetime from sqlalchemy import create_engine from sqlalchemy import Column, Integer, String, DateTime from sqlalchemy.orm import sessionmaker from sqlalchemy.exc import SQLAlchemyError from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.engine.url import URL engine = create_engine('sqlite://') Base = declarative_base() class TestTable(Base): __tablename__ = 'Test Table' id = Column(Integer, primary_key=True) key = Column(String, nullable=False) val = Column(String) ctime = Column(DateTime, default=datetime.utcnow) mtime = Column(DateTime) # create tables Base.metadata.create_all(bind=engine) # create session Session = sessionmaker() Session.configure(bind=engine) session = Session() data = {'a': 5566, 'b': 9527, 'c': 183} try: for _key, _val in data.items(): row = TestTable(key=_key, val=_val) session.add(row) session.commit() except SQLAlchemyError as e: print(e) finally: session.close() but there is no sqlalchemy.exc.ArgumentError. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread.

[crazyguitar]

@John-Male

Oh! it seems like you encountered a name conflict issue. I think that using DateTime

class TestTable(Base):
    __tablename__ = 'Test Table'
    id   = Column(Integer, primary_key=True)
    key  = Column(String, nullable=False)
    val  = Column(String)
    ctime = Column(DateTime, default=datetime.utcnow)

is fine because name conflict should be handled by programmers. However, you remind me that DateTime(timezone=True) would be useful if datetime columns are timezone sensitive. Thanks!