Considering following peewee backed python code, how to filter data in a table based on values across rows in another table
e.g.
if I want to get a note in Note table having all java
, lambda
, generics
tags in customtags
x
#!/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))
I am really not having idea how to modify my code the get the data above mentioned, I know that issue is in following code
notes = Note.select().join(CustomTag, peewee.JOIN.LEFT_OUTER,on=(Note.id == CustomTag.note_id)).order_by(Note.name)
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Answer
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)))