use flask-sqlalchemy for the main db

• added the Flask-SqlAlchemy and Flask-Migrate dependencies to replace session and migration boilerplate code
• Updated all the orm queries to the new SqlAlchemy 2 API

added 12 commits

• 6e62575f...b7fe7e0f - 11 commits from branch develop
• 538048a9 - Merge branch 'develop' into feature/COMP-170_part_2_introduce_flask_sqlalchemy

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added 1 commit

• 14411075 - use flask-migrate for the migrations

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added 1 commit

• 6b736da7 - use sqlalchemy2 syntax everywhere

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added 1 commit

• 0f775788 - also use flask-sqlalchemy for the survey db

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marked this merge request as ready

changed the description

When I run flask db migrate it detects that the enum name for charging structure feetype is different because of the naming changes:

def upgrade():
    # ### commands auto generated by Alembic - please adjust! ###
    with op.batch_alter_table('charging_structure', schema=None) as batch_op:
        batch_op.alter_column('fee_type',
               existing_type=postgresql.ENUM('flat_fee', 'usage_based_fee', 'combination', 'no_charge', 'other', name='fee_type'),
               type_=sa.Enum('flat_fee', 'usage_based_fee', 'combination', 'no_charge', 'other', name='feetype'),
               existing_nullable=True)

    # ### end Alembic commands ###


def downgrade():
    # ### commands auto generated by Alembic - please adjust! ###
    with op.batch_alter_table('charging_structure', schema=None) as batch_op:
        batch_op.alter_column('fee_type',
               existing_type=sa.Enum('flat_fee', 'usage_based_fee', 'combination', 'no_charge', 'other', name='feetype'),
               type_=postgresql.ENUM('flat_fee', 'usage_based_fee', 'combination', 'no_charge', 'other', name='fee_type'),
               existing_nullable=True)

    # ### end Alembic commands ###

..either we should keep the old name, or reapply migrations to fix the enum in postgres - you can make a decision and I will follow

Other than this, the changes look good to me and can be merged

Yes; this is just the enum in the db metadata though and it doesnt have any functional effect, so I was thinking to just include this migration in the next useful one as to not have an unnecessary migration. The reason its detected now is that in Flask-SqlAlchemy the compare-type setting defaults to true while in bare SqlAlchemy it defaults to false. The alternative would be to rename the python enum from FeeType to Fee_Type but I dont want to do that.

mentioned in commit 41de7f69

merged