ORM class attributes that are mapped to database table: provide as built-in method. Generally, provide ORM class-level info.

[taibit]

I wanted a list of ORM class attributes that are mapped to db columns.

I found the built-in (private) function _orm_columns() in the source code file /lib/sqlalchemy/orm/base.py which worked when my ORM class attributes were not re-named.

But when I made an ORM attribute different from the db column, the _orm_columns() no longer worked.

Generally, there seems to be a need for info about the ORM class that is distinct from the mapping of that class to a db table. There does not seem to be a place for that info that is provided out-of-the-box as far as I can tell.

My a solution for my particular issue that includes my code is posted on stackoverflow at: http://stackoverflow.com/questions/27947294/when-the-sqlalchemy-orm-class-attributes-are-different-from-database-columns-ho

BTW, is there a reason that the function _orm_columns() is private and not documented? Otherwise, users struggle to come up with their own solution as in: http://stackoverflow.com/questions/1958219/convert-sqlalchemy-row-object-to-python-dict/24748320#24748320

On the positive side, it's nice that sqlalchemy and python provide the flexible structure for me to create a simple solution for my particular need as is documented in Mixin and Custom Base Classes http://docs.sqlalchemy.org/en/rel_0_9/orm/extensions/declarative/mixins.html

[Mike Bayer]

this is already implemented:

from sqlalchemy import *
from sqlalchemy.orm import *
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import inspect

Base = declarative_base()

class A(Base):
    __tablename__ = 'a'
    id = Column(Integer, primary_key=True)
    x = Column(Integer)
    y = Column(Integer)

print inspect(A).c
print inspect(A).c.x
print inspect(A).column_attrs
print inspect(A).column_attrs.x
print inspect(A).column_attrs.x.expression

http://docs.sqlalchemy.org/en/rel_0_9/core/inspection.html

http://docs.sqlalchemy.org/en/rel_0_9/orm/mapping_api.html#sqlalchemy.orm.mapper.Mapper.all_orm_descriptors

http://docs.sqlalchemy.org/en/rel_0_9/orm/mapping_api.html#sqlalchemy.orm.mapper.Mapper.columns

http://docs.sqlalchemy.org/en/rel_0_9/orm/mapping_api.html#sqlalchemy.orm.mapper.Mapper.column_attrs

http://docs.sqlalchemy.org/en/rel_0_9/orm/mapping_api.html#sqlalchemy.orm.mapper.Mapper.c

[Mike Bayer]

• add new section to ORM referring to runtime inspection API, more links, attempt to fix #3290

→ <<cset 41307cd7339a>>

[Mike Bayer]

• add new section to ORM referring to runtime inspection API, more links, attempt to fix #3290

→ <<cset b77f0a0f7d2a>>