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I am writing a migration in alembic but seems impossible to me the change the value of server_defaults from something to nothing.
My code:
op.alter_column("foo", sa.Column("bar", sa.DateTime(timezone=False), server_default=None, nullable=True)) If i check after the migration the default is still NOW()
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This file provides documentation on Alembic migration directives. The directives here are used within user-defined migration files, within the upgrade() and downgrade() functions, as well as any functions further invoked by those. All directives exist as methods on a class called Operations .
First, specify the name of the table to which the column you want to change belongs in the ALTER TABLE clause. Second, give the name of column whose data type will be changed in the ALTER COLUMN clause. Third, provide the new data type for the column after the TYPE keyword.
We can select a column with its alias name using the . label() method in SQLAlchemy. Sometimes we got the requirements to show a function result or column name with a different name, you can use the . label() method there.
You can do something like this: DELETE FROM alembic_version WHERE version_num='3aae6532b560'; INSERT INTO alembic_version VALUES ('3aae6532b560'); Above query could be done in one query by limiting number of deleted rows, but limiting within DELETE query is different between different databases engines.
To rename a column as of Alembic 0.9.5 I had to alter my migration to read as follows:
op.alter_column('my_table', 'old_col_name', nullable=False, new_column_name='new_col_name') That's not how op.alter_column() works. Pass it arguments about what to change, not a new sa.Column instance.
op.alter_column('my_table', 'my_column', server_default=None) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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