On 08/15/2010 11:36 AM, mclovin wrote: > I am new to SQL and SQLalchemy, but say I have a class like this: > > class User(Base): > __tablename__ = "users" > > id = Column(Integer, primary_key=True) > name = Column(String, unique=True) > join = Column(DateTime) > infractions =Column(Integer) > posts = Column(Integer) > > def __init__(self, name): > self.name = name > self.join = datetime.datetime.now() > self.infractions = 0 > self.posts = 0 > > > but I wanted to change it to this: > class User(Base): > __tablename__ = "users" > > id = Column(Integer, primary_key=True) > name = Column(String, unique=True) > join = Column(DateTime) > infractions =Column(Integer) > #posts = Column(Integer) REMOVE POSTS > bannedTill = Column(DateTime) #ADD BANNEDTILL > > def __init__(self, name): > self.name = name > self.join = datetime.datetime.now() > self.infractions = 0 > self.bannedTill = datetime.datetime.now() > > > Where I remove the column posts and add a column "bannedTill". What > are the steps to update my table "users" to reflect these changes > without losing the data that is already in the table (I will populate > my new field manually). >
What you want is called schema migration. It's a big topic, but the simplest way is to manually execute raw SQL commands to add/remove columns. For example, in PostgreSQL: BEGIN; ALTER TABLE users DROP COLUMN posts; ALTER TABLE users ADD COLUMN bannedTill TIMESTAMP; COMMIT; Alternatively, there is a package called sqlalchemy-migrate <http://code.google.com/p/sqlalchemy-migrate/> that offers a more sophisticated way to migrate schemas. -Conor -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
