Fix migration to handle case where users table already exists

migrations/versions/2_add_users_table_and_update_todos.py

@@ -16,7 +16,14 @@ depends_on = None
 
 
 def upgrade():
-    # Create users table
+    # Create users table if it doesn't exist
+    from sqlalchemy.exc import OperationalError
+    try:
+        # Use inspector to check if the table exists
+        from sqlalchemy import inspect
+        conn = op.get_bind()
+        inspector = inspect(conn)
+        if 'users' not in inspector.get_table_names():
             op.create_table(
                 'users',
                 sa.Column('id', sa.Integer(), nullable=False),
@@ -37,8 +44,20 @@ def upgrade():
             op.create_index(op.f('ix_users_email'), 'users', ['email'], unique=True)
             op.create_index(op.f('ix_users_id'), 'users', ['id'], unique=False)
             op.create_index(op.f('ix_users_username'), 'users', ['username'], unique=True)
+    except OperationalError:
+        # Table already exists, skip creation
+        pass
 
-    # Add owner_id column to todos table
+    # Add owner_id column to todos table if it doesn't exist
+    from sqlalchemy.exc import OperationalError
+
+    # Check if owner_id column exists in todos table
+    conn = op.get_bind()
+    inspector = inspect(conn)
+    columns = [col['name'] for col in inspector.get_columns('todos')]
+
+    if 'owner_id' not in columns:
+        try:
             op.add_column('todos', sa.Column('owner_id', sa.Integer(), nullable=True))
 
             # Create foreign key from todos to users
@@ -53,17 +72,46 @@ def upgrade():
 
             # Make owner_id non-nullable after updating existing todos
             op.alter_column('todos', 'owner_id', nullable=False)
+        except OperationalError as e:
+            # Log the error but continue
+            print(f"Operation failed with error: {str(e)}")
+            # If this is because the column already exists, we can continue
+            pass
 
 
 def downgrade():
-    # Drop foreign key constraint
-    op.drop_constraint('fk_todos_owner_id_users', 'todos', type_='foreignkey')
+    from sqlalchemy import inspect
+    from sqlalchemy.exc import OperationalError
 
-    # Drop owner_id column from todos
+    conn = op.get_bind()
+    inspector = inspect(conn)
+
+    # Check if the constraint exists before trying to drop it
+    try:
+        constraints = inspector.get_foreign_keys('todos')
+        constraint_name = 'fk_todos_owner_id_users'
+        fk_exists = any(constraint['name'] == constraint_name for constraint in constraints)
+        if fk_exists:
+            op.drop_constraint('fk_todos_owner_id_users', 'todos', type_='foreignkey')
+    except OperationalError:
+        pass
+
+    # Check if owner_id column exists before trying to drop it
+    columns = [col['name'] for col in inspector.get_columns('todos')]
+    if 'owner_id' in columns:
         op.drop_column('todos', 'owner_id')
 
-    # Drop users table
+    # Check if users table exists before trying to drop it
+    if 'users' in inspector.get_table_names():
+        # Check for each index before dropping
+        indices = inspector.get_indexes('users')
+        index_names = [index['name'] for index in indices]
+
+        if 'ix_users_username' in index_names:
             op.drop_index(op.f('ix_users_username'), table_name='users')
+        if 'ix_users_id' in index_names:
             op.drop_index(op.f('ix_users_id'), table_name='users')
+        if 'ix_users_email' in index_names:
             op.drop_index(op.f('ix_users_email'), table_name='users')
+
         op.drop_table('users')