I have this table with some data in it:
Name:
users
Columns:
id (primary key) | name
Rows:
1) 1 | "name 1"
2) 2 | "name 2"
3) 3 | "name 3"
Relationships:
settings
I need to create this table:
Name:
user_settings
Columns:
user_id (primary_key, foreign_key) | some_key
Relationships:
user
Using alembic revision I got this upgrade script:
def upgrade():
op.create_table('user_settings',
sa.Column('user_id', sa.Integer(), nullable=False),
sa.Column('some_key', sa.String(), nullable=True),
sa.ForeignKeyConstraint(['user_id'], ['users.id']),
sa.PrimaryKeyConstraint('user_id')
)
After alembic upgrade it creates an empty user_settings table (as expected). But I need to use settings values for each existing user immediately after upgrade. For example, when I get user value with following SQLAlchemy query:
user = User.query.filter(User.id == id).first()
I should be able to access user settings something like that:
value = user.settings.some_key
But it is not possible right after upgrade because user_settings table is empty.
How to fill new table with mapped values right after upgrade? So that when I run alembic upgrade I should get a table with values, not an empty table:
Name:
user_settings
Columns:
user_id (primary_key, foreign_key) | some_key
Rows:
1) 1 | "default value"
2) 2 | "default value"
3) 3 | "default value"
Relationships:
user
I can think of two approaches:
- Manually perform some actions to fill new table.
- Don't fill new table and write function something like
settings_get_or_create()(which will create new settings for user if settings row for that user don't exists).
There is other approaches? What is best?
I'm using Alembic, SQLAlchemy and SQL database.
