[英]How to find nested value in postgres JSONB using sqlalchemy?
I have a postgres table with JSONB column name entity
.我有一个带有 JSONB 列名entity
的 postgres 表。 The example of json structure is: json结构示例为:
{
"some_key": "some value",
"properties": {
"name": ["name_value"],
}
}
I need to find records by name_value
.我需要按name_value
查找记录。 I can get it by using query:我可以通过使用查询得到它:
SELECT entity FROM my_table where entity->'properties' @> {"name": ["name_value"]};
The problem is: I cannot find the way to create that same query using sqlalchemy ORM.问题是:我找不到使用 sqlalchemy ORM 创建相同查询的方法。
Update : My model is made dynamic, because multiple tables are using same structure just the different table name.更新:我的 model 是动态的,因为多个表使用相同的结构,只是表名不同。 Here is the code:这是代码:
...
Base = declarative_base(engine)
class ForeignBase(AbstractConcreteBase, Base):
pass
def make_model(name):
class Entity(ForeignBase):
__tablename__ = name
__mapper_args__ = {"polymorphic_identity": name, "concrete": True}
__table_args__ = {"extend_existing": True}
id = Column(String, primary_key=True)
entity = Column(JSONB, nullable=True)
...
configure_mappers()
return Entity
And then I use 3 functions to initiate my Models and get one I currently need:然后我使用 3 个函数来启动我的模型并获得我当前需要的一个:
def get_model_list():
tables_names_list = get_table_name_list()
model_list = [make_model(PREFIX + table_name) for table_name in tables_names_list]
return model_list
def get_tables_dict():
return {table.__tablename__: table for table in ForeignBase.__subclasses__()}
def get_table_object(table_name):
return get_tables_dict().get(table_name)
You can use the following SQLAlchemy expression.您可以使用以下 SQLAlchemy 表达式。 The Operator @> is contains() in SQLAlchemy for JSONB columns运算符 @> 是 JSONB 列的 SQLAlchemy 中的 contains()
Session().query(MyTable).filter(MyTable.entity["properties"].contains({"name": ["name_value"]})).with_entities(MyTable.entity).all()
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