peewee 检查自动创建的 id 不在子查询的结果中

Question

我有下一个数据结构：

from enum import IntEnum, unique
from pathlib import Path
from datetime import datetime
from peewee import *

@unique
class Status(IntEnum):
    CREATED = 0
    FAIL = -1
    SUCCESS = 1

db_path = Path(__file__).parent / "test.sqlite"
database = SqliteDatabase(db_path)

class BaseModel(Model):
    class Meta:
        database = database

class Unit(BaseModel):
    name = TextField(unique=True)
    some_field = TextField(null=True)
    created_at = DateTimeField(default=datetime.now)

class Campaign(BaseModel):
    id_ = AutoField()
    created_at = DateTimeField(default=datetime.now)

class Task(BaseModel):
    id_ = AutoField()
    status = IntegerField(default=Status.CREATED)
    unit = ForeignKeyField(Unit, backref="tasks")
    campaign = ForeignKeyField(Campaign, backref="tasks")

下一个代码创建单位、活动和任务：

def fill_units(count):
    units = []
    with database.atomic():
        for i in range(count):
            units.append(Unit.create(name=f"unit{i}"))
    return units

def init_campaign(count):
    units = Unit.select().limit(count)
    with database.atomic():
        campaign = Campaign.create()
        for unit in units:
            Task.create(unit=unit, campaign=campaign)
    return campaign

当我尝试向现有 广告系列 添加更多单位时出现问题。我需要 select 单位，在这个活动中还没有使用过。在 SQL 中，我可以使用下一个查询来做到这一点：

SELECT * FROM unit WHERE id NOT IN (SELECT unit_id FROM task WHERE campaign_id = 1) LIMIT 10

但是如何使用 peewee 做到这一点？

我找到的唯一方法是：

def get_new_units_for_campaign(campaign, count):
    unit_names = [task.unit.name for task in campaign.tasks]
    units = Unit.select().where(Unit.name.not_in(unit_names)).limit(count)
    return units

它以某种方式起作用，但我 100% 确定这是实现它的最愚蠢的方法。你能告诉我实现这个的正确方法吗？

Answer 1

我终于找到了这个：

Unit.select().where(Unit.id.not_in(campaign.tasks.select(Task.unit))).limit(10)

产生

SELECT "t1"."id", "t1"."name", "t1"."some_field", "t1"."created_at" FROM "unit" AS "t1" WHERE ("t1"."id" NOT IN (SELECT "t2"."unit_id" FROM "task" AS "t2" WHERE ("t2"."campaign_id" = 1))) LIMIT 10

与我在问题中提供的 SQL 查询匹配。

P.S。我做了一些研究，它似乎是一个正确的实现，但如果有人纠正我并展示更好的方法，我将不胜感激 ~~(if exist)~~.

peewee 检查自动创建的 id 不在子查询的结果中

peewee check automatically created id not in result of subquery

python

peewee