On 01/10/2017 03:33 AM, Chris Withers wrote:
Okay, so this worked:
op.execute(CreateSequence(Sequence("observation_id_seq")))
op.add_column('observation', sa.Column(
'id', sa.Integer(), nullable=False,
server_default=sa.text("nextval('observation_id_seq'::regclass)")
))
op.drop_constraint('observation_pkey', table_name='observation')
op.create_primary_key('observation_pkey', 'observation', ['id'])
...but how come my original attempt didn't?
when you add a NOT NULL column it needs to be able to create a value for
all the existing rows, so yeah giving it a server default so it can do
that is the right way to go. you can look in your column and see 1, 2,
3, 4, 5, 6, 7, ... that it got from that.
cheers,
Chris
On 10/01/2017 08:03, Chris Withers wrote:
So, I screwed up and realised I really want an auto-incrementing integer
as the primary key for a bunch of tables.
I've changed my models, got all the tests passing and now I need to get
the migrations done, I have:
op.add_column('observation',
sa.Column('id', sa.Integer(), nullable=False,
autoincrement=True))
op.drop_constraint('observation_pkey', table_name='observation')
op.create_primary_key('observation_pkey', 'observation', ['id'])
According to this answer, this should work:
http://stackoverflow.com/a/19262262/216229
...but when running the migration, I get:
sqlalchemy.exc.IntegrityError: (psycopg2.IntegrityError) column "id"
contains null values
[SQL: 'ALTER TABLE observation ADD COLUMN id INTEGER NOT NULL']
...so what am I doing wrong?
cheers,
Chris
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