On 10/9/15 8:33 AM, Richard Gerd Kuesters wrote: > Hello! I was working with a JSONB column in postgres and I noticed > that no updates were issued when changing some inside value, so I have > to issue "*flag_modified*" everytime I change my JSONB attribute. > Here's a sample code that shows this:
I see no usage of Mutable, which is required if you want to detect updates within a JSON value. See the notes on the JSON(B) types for this: http://docs.sqlalchemy.org/en/rel_1_0/dialects/postgresql.html?highlight=jsonb#sqlalchemy.dialects.postgresql.JSONB The |JSON| <http://docs.sqlalchemy.org/en/rel_1_0/dialects/postgresql.html?highlight=jsonb#sqlalchemy.dialects.postgresql.JSON> type, when used with the SQLAlchemy ORM, does not detect in-place mutations to the structure. In order to detect these, the |sqlalchemy.ext.mutable| <http://docs.sqlalchemy.org/en/rel_1_0/orm/extensions/mutable.html#module-sqlalchemy.ext.mutable> extension must be used. This extension will allow “in-place” changes to the datastructure to produce events which will be detected by the unit of work. See the example at |HSTORE| <http://docs.sqlalchemy.org/en/rel_1_0/dialects/postgresql.html?highlight=jsonb#sqlalchemy.dialects.postgresql.HSTORE> for a simple example involving a dictionary. > > # -*- coding: utf-8 -*- > > from __future__ import unicode_literals > > > from sqlalchemy import Column, Integer, create_engine > from sqlalchemy.orm import Session > from sqlalchemy.orm.attributes import flag_modified > from sqlalchemy.ext.hybrid import hybrid_property > from sqlalchemy.ext.declarative import declarative_base > from sqlalchemy.dialects.postgresql import JSONB > > > Base = declarative_base() > > > class EntityA(Base): > __tablename__ = 'entity_a' > > a_id = Column(Integer, primary_key=True) > a_value = Column(JSONB, nullable=False) > > > class EntityB(Base): > __tablename__ = 'entity_b' > > b_id = Column(Integer, primary_key=True) > _b_value = Column(JSONB, nullable=False) > > @hybrid_property > def b_value(self): > return self._b_value > > @b_value.setter > def b_value(self, value): > self._b_value = value > > > class EntityC(Base): > __tablename__ = 'entity_c' > > c_id = Column(Integer, primary_key=True) > _c_value = Column(JSONB, nullable=False) > > @hybrid_property > def c_value(self): > return self._c_value > > @c_value.setter > def c_value(self, value): > self._c_value = value > flag_modified(self, '_c_value') > > > if __name__ == '__main__': > engine = > create_engine('postgresql://test:test123@127.0.0.1/testing', > echo=False) > Base.metadata.create_all(engine) > session = Session(engine) > > # testing A, without hybrid property > > a_test = EntityA() > a_test.a_value = dict(hello='world', test=1, enabled=True) > > session.add(a_test) > session.commit() > > print('EntityA, after insert:', a_test.a_value) > > json_obj_a = a_test.a_value > json_obj_a['hello'] = 'foo' > a_test.a_value = json_obj_a > > session.commit() > > # assert a_test.a_value.get('hello') == 'foo' # error > assert a_test.a_value.get('hello') == 'world' # works > > print('EntityA, after update:', a_test.a_value) > > # testing B, with hybrid property and no flag_modified > > b_test = EntityB() > b_test.b_value = dict(hello='world', test=1, enabled=True) > > session.add(b_test) > session.commit() > > print('EntityB, after insert:', b_test.b_value) > > json_obj_b = b_test.b_value > json_obj_b['hello'] = 'bar' > b_test.b_value = json_obj_b > > session.commit() > > # assert b_test.b_value.get('hello') == 'bar' # error > assert b_test.b_value.get('hello') == 'world' # works > > print('EntityB, after update:', b_test.b_value) > > # testing C, with hybrid property and flag_modified > > c_test = EntityC() > c_test.c_value = dict(hello='world', test=1, enabled=True) > > session.add(c_test) > session.commit() > > print('EntityC, after insert:', c_test.c_value) > > json_obj_c = c_test.c_value > json_obj_c['hello'] = 'baz' > c_test.c_value = json_obj_c > > session.commit() > > assert c_test.c_value.get('hello') == 'baz' # works > # assert c_test.c_value.get('hello') == 'world' # error > > print('EntityC, after update:', c_test.c_value) > > # end test > session.close() > > Base.metadata.drop_all(engine) > > > extra data, if needed: > > $ pip freeze > psycopg2==2.6.1 > SQLAlchemy==1.0.8 > > $ postgres --version > postgres (PostgreSQL) 9.4.4 > > $ python --version > Python 2.7.10 > > $ uname -a > Linux marrow.polluxnet 4.2.3-1-ARCH #1 SMP PREEMPT Sat Oct 3 > 18:52:50 CEST 2015 x86_64 GNU/Linux > > > thanks a lot, if any other information is needed, please let me know. > > > best regards, > richard. > -- > You received this message because you are subscribed to the Google > Groups "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send > an email to sqlalchemy+unsubscr...@googlegroups.com > <mailto:sqlalchemy+unsubscr...@googlegroups.com>. > To post to this group, send email to sqlalchemy@googlegroups.com > <mailto:sqlalchemy@googlegroups.com>. > Visit this group at http://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. 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