Database¶

Notes and Miscellaneous Informations¶

With alembic a migration that involve dropping a column with a constraints must be handled carefully. First you must find out the name of the constraint running a command like:

SHOW CREATE TABLE <tablename>;

For example the constraint name is bookmarks_ibfk_3, so you can now create the alembic operation that will first drop the contraint and then the column and the table:

def upgrade():
    op.drop_constraint('bookmarks_ibfk_3', 'bookmarks', 'foreignkey')
    op.drop_column("bookmarks", "category_id")
    op.drop_table("categories")