Generating User IDs in Python

Question

I've created a simple DB using SQLAlchemy in python and there is a column for a unique user ID for each user entered. I want to have a running counter that supplies the next ID whenever a new User is added.

What would be the best way to implement this? A column with the value of the last id number, or would that be an entirely separate table (seems wasteful.) Is there a way for it to check the last User.id and add one? Here is the User base class:

class User(Base):
    __tablename__ = 'users'

    id = Column(Integer, primary_key = True)
    email_address = Column(String, nullable = False)
    username = Column(String, nullable = False)
    password = Column(String, nullable = False)
    first_name = Column(String)
    full_name = Column(String)
    join_date = Column(DateTime, default=func.now()) # enters the time upon initialization

    def __init__(self, email_address, username, password):
        self.email_address = email_address
        self.username = username
        self.password = password

    def __repr__(self):
        return "<User('%s', '%s', '%s', '%s')>" % (self.email_address, self.username, self.password, self.join_date)

Answer 1

Read this: http://www.sqlalchemy.org/docs/core/schema.html#defining-sequences.

Key generation is a part of the database.

You simply want the database to assign unique keys.