peewee：如何根据另一个 table 中跨行的值过滤 table 中的数据

Question

考虑以下 peewee 支持的 python 代码，如何根据另一个 table

中跨行的值过滤 table 中的数据

例如如果我想在 Note table 中获得一个注释，其中包含 java、lambda、generics 中的所有标签 customtags

#!/usr/bin/env python3

import peewee
import datetime

db = peewee.SqliteDatabase('test.db')

class Note(peewee.Model):
    id = peewee.AutoField()
    name = peewee.CharField()
    text = peewee.CharField()
    created = peewee.DateField(default=datetime.date.today)

    class Meta:

        database = db
        db_table = 'notes'

class CustomTag(peewee.Model):
    id = peewee.AutoField()
    note = peewee.ForeignKeyField(Note, backref='notes')
    tag = peewee.CharField()

    class Meta:

        database = db
        db_table = 'customtags'
        indexes = ((("note_id", "tag"), True),)

Note.drop_table()
CustomTag.drop_table()
Note.create_table()
CustomTag.create_table()

note1 = Note.create(name="note1",text='Java 8 lambda with generics')
note1.save()
CustomTag.insert(note=note1, tag='java').on_conflict_ignore(True)
CustomTag.insert(note=note1, tag='lambda').on_conflict_ignore(True)
CustomTag.insert(note=note1, tag='generics').on_conflict_ignore(True)

note2 = Note.create(name="note2",text='Core Java concepts',
        created=datetime.date(2018, 10, 20))
note2.save()
CustomTag.insert(note=note2, tag='java').on_conflict_ignore(True)

note3 = Note.create(name="note3",text='Java collection framework',
        created=datetime.date(2018, 10, 22))
note3.save()
CustomTag.insert(note=note3, tag='java').on_conflict_ignore(True)

note4 = Note.create(name="note4",text='Java NIO packageJava nio package')
note4.save()
CustomTag.insert(note=note4, tag='java').on_conflict_ignore(True)

notes = Note.select().join(CustomTag, peewee.JOIN.LEFT_OUTER,on=(Note.id == CustomTag.note_id)).order_by(Note.name)

for note in notes:
    print('{} with text {} on {}'.format(note.name, note.text, note.created))

我真的不知道如何修改我的代码来获取上面提到的数据，我知道问题出在下面的代码中

notes = Note.select().join(CustomTag, peewee.JOIN.LEFT_OUTER,on=(Note.id == CustomTag.note_id)).order_by(Note.name)

Answer 1

e.g. if I want to get a note in Note table having all java, lambda, generics tags in customtags

tags = ['foo', 'bar', 'baz']
query = (Note
         .select()
         .join(CustomTag)
         .where(CustomTag.tag.in_(tags))
         .group_by(Note)
         .having(fn.COUNT(CustomTag.id) == len(tags)))

Answer 2

您的插入语句中似乎缺少 execute()。应该从每一行开始更正...

CustomTag.insert(note=note1, tag='java').on_conflict_ignore(True).execute()

我在这里包含了一些改进版本的 coleifer 答案，结果也包括标签列表...

from peewee import fn 

filter_tags = ['java', 'lambda', 'generics']
notes = (Note
         .select(Note, fn.GROUP_CONCAT(CustomTag.tag,',').alias('tags'))
         .join(CustomTag)
         .where(CustomTag.tag.in_(filter_tags))
         .group_by(Note)
         .having(fn.COUNT(CustomTag.id) >= len(filter_tags)))

for note in notes:
    print(f'name : {note.name} text: {note.text} tags: {note.tags} created : {note.created}')

peewee：如何根据另一个 table 中跨行的值过滤 table 中的数据

peewee : how to filter data in a table based on values across rows in another table

python

sql

peewee