135 lines
4.3 KiB
Python
135 lines
4.3 KiB
Python
import sqlalchemy as sa
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from sqlalchemy_utils import batch_fetch, with_backrefs
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from tests import TestCase
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class TestBatchFetchDeepRelationships(TestCase):
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def create_models(self):
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class User(self.Base):
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__tablename__ = 'user'
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id = sa.Column(sa.Integer, autoincrement=True, primary_key=True)
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name = sa.Column(sa.Unicode(255))
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class Category(self.Base):
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__tablename__ = 'category'
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id = sa.Column(sa.Integer, primary_key=True)
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name = sa.Column(sa.Unicode(255))
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class Article(self.Base):
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__tablename__ = 'article'
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id = sa.Column(sa.Integer, primary_key=True)
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name = sa.Column(sa.Unicode(255))
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category_id = sa.Column(sa.Integer, sa.ForeignKey(Category.id))
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category = sa.orm.relationship(
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Category,
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primaryjoin=category_id == Category.id,
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backref=sa.orm.backref(
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'articles'
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)
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)
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article_tag = sa.Table(
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'article_tag',
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self.Base.metadata,
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sa.Column(
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'article_id',
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sa.Integer,
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sa.ForeignKey('article.id', ondelete='cascade')
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),
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sa.Column(
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'tag_id',
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sa.Integer,
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sa.ForeignKey('tag.id', ondelete='cascade')
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)
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)
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class Tag(self.Base):
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__tablename__ = 'tag'
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id = sa.Column(sa.Integer, primary_key=True)
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name = sa.Column(sa.Unicode(255))
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articles = sa.orm.relationship(
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Article,
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secondary=article_tag,
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backref=sa.orm.backref(
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'tags'
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)
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)
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self.User = User
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self.Category = Category
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self.Article = Article
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self.Tag = Tag
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def init_data(self):
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articles = [
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self.Article(name=u'Article 1'),
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self.Article(name=u'Article 2'),
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self.Article(name=u'Article 3'),
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self.Article(name=u'Article 4'),
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self.Article(name=u'Article 5')
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]
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self.session.add_all(articles)
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self.session.flush()
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tags = [
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self.Tag(name=u'Tag 1'),
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self.Tag(name=u'Tag 2'),
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self.Tag(name=u'Tag 3')
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]
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articles[0].tags = tags
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articles[3].tags = tags[1:]
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category = self.Category(name=u'Category #1')
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category.articles = articles[0:2]
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category2 = self.Category(name=u'Category #2')
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category2.articles = articles[2:]
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self.session.add(category)
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self.session.add(category2)
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self.session.commit()
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def test_supports_empty_related_entities(self):
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category = self.Category(name=u'Category #1')
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self.session.add(category)
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self.session.commit()
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categories = self.session.query(self.Category).all()
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batch_fetch(
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categories,
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'articles',
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'articles.tags'
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)
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query_count = self.connection.query_count
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assert not categories[0].articles
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assert self.connection.query_count == query_count
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def test_deep_relationships(self):
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self.init_data()
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categories = self.session.query(self.Category).all()
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batch_fetch(
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categories,
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'articles',
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'articles.tags'
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)
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query_count = self.connection.query_count
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categories[0].articles[0].tags
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assert self.connection.query_count == query_count
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categories[1].articles[1].tags
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assert self.connection.query_count == query_count
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def test_many_to_many_backref_population(self):
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self.init_data()
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categories = self.session.query(self.Category).all()
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batch_fetch(
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categories,
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'articles',
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with_backrefs('articles.tags'),
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)
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query_count = self.connection.query_count
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tags = categories[0].articles[0].tags
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tags2 = categories[1].articles[1].tags
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tags[0].articles
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tags2[0].articles
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names = [article.name for article in tags[0].articles]
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assert u'Article 1' in names
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assert self.connection.query_count == query_count
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