[Sqlalchemy-tickets] Issue #4351: like() in association_proxy (zzzeek/sqlalchemy)

[Abdeali K. <iss...@bi...>]

New issue 4351: like() in association_proxy
https://bitbucket.org/zzzeek/sqlalchemy/issues/4351/like-in-association_proxy

Abdeali Kothari:

This is an issue I'm creating for the situation described in: https://stackoverflow.com/questions/36017947/filter-with-like-on-sqlalchemy-association-proxy

I am creating the issue here to understand if there is an interest in adding this functionality to the core library.

If there is interest in adding like() filters to association proxies i would be interested in contributing and making a pull-request for it

The example here is:

```
class Institution(Base):

    entity_id = Column(
        String(8, u'SQL_Latin1_General_CP1_CI_AS'),
        ForeignKey(Entity.entity_id),
        primary_key=True)
    entity = relationship(Entity, uselist=False)
    name = association_proxy('entity', 'entity_proper_name')

```

and the outputs:
```
query = s.query(Institution).filter(Institution.name=='Correct Name')
# works fine

query = s.query(Institution).filter(Institution.name.like('%Correct N%')
# AttributeError: 'AssociationProxy' object has no attribute 'like'
```

A possible workaround is:
```
from sqlalchemy.ext.associationproxy import AssociationProxy

def like_filter(attr, *args, **kwargs):
    filter_attr = attr
    if isinstance(filter_attr, AssociationProxy):  # If assoc_proxy get remote_attr as like() doesnt work
        filter_attr = filter_attr.remote_attr
    return filter_attr.like(*args, **kwargs)
```