musicmuster/archive/db_experiments.py
2023-10-28 11:30:37 +01:00

85 lines
2.0 KiB
Python
Executable File

#!/usr/bin/env python3
from sqlalchemy import create_engine, String, update, bindparam, case
from sqlalchemy.orm import (
DeclarativeBase,
Mapped,
mapped_column,
sessionmaker,
scoped_session,
)
from typing import Generator
from contextlib import contextmanager
db_url = "sqlite:////tmp/rhys.db"
class Base(DeclarativeBase):
pass
class Rhys(Base):
__tablename__ = "rhys"
id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
ref_number: Mapped[int] = mapped_column()
name: Mapped[str] = mapped_column(String(256), index=True)
def __init__(self, session, ref_number: int, name: str) -> None:
self.ref_number = ref_number
self.name = name
session.add(self)
session.flush()
@contextmanager
def Session() -> Generator[scoped_session, None, None]:
Session = scoped_session(sessionmaker(bind=engine))
yield Session
Session.commit()
Session.close()
engine = create_engine(db_url)
Base.metadata.create_all(engine)
inital_number_of_records = 10
def move_rows(session):
new_row = 6
with Session() as session:
# new_record = Rhys(session, new_row, f"new {new_row=}")
# Move rows
stmt = (
update(Rhys)
.where(Rhys.ref_number > new_row)
# .where(Rhys.id.in_(session.query(Rhys.id).order_by(Rhys.id.desc())))
.values({Rhys.ref_number: Rhys.ref_number + 1})
)
session.execute(stmt)
sqla_map = []
for k, v in zip(range(11), [0, 1, 2, 3, 4, 7, 8, 10, 5, 6, 9]):
sqla_map.append({"oldrow": k, "newrow": v})
# for a, b in sqla_map.items():
# print(f"{a} > {b}")
with Session() as session:
for a in range(inital_number_of_records):
_ = Rhys(session, a, f"record: {a}")
stmt = update(Rhys).values(
ref_number=case(
{item['oldrow']: item['newrow'] for item in sqla_map},
value=Rhys.ref_number
)
)
session.connection().execute(stmt, sqla_map)