How to increase a counter in SQLAlchemy

Question

Suppose I have table tags which has a field count that indicates how many items have been tagged with the given tag.

How do I

Answer 1

I got here following a tutorial for FastAPI, SQLAlchemy and databases (async). After various tries I finally got it working with following code in my crud.py / control layer.

async def inc_counter():
    query = counters.select(counters.c.id==1)
    current_val = await database.fetch_val(query=query, column=1)
    query = counters.update().where(counters.c.id==1).values(counter=current_val+1).returning(counters.c.counter)
    return await database.execute(query=query)

My table looks like this:

counters = Table('counters', metadata,
    Column('id', Integer, primary_key=True),
    Column('counter', Integer)
)