Re: [sqlalchemy] ORM: walk() related objects
Final version:
def walk_related(obj, enableDuplicates=False, level=-1, memo=None):
memo = memo or set()
insp = inspect(obj)
for relobj in insp.mapper.cascade_iterator('delete', insp):
if enableDuplicates or relobj[0] not in memo:
memo.add(relobj[0])
yield level, relobj[0]
relatedObjects = walk_related(relobj[0],
enableDuplicates=enableDuplicates, level=level + 1, memo=
memo)
for walked_relobj in relatedObjects:
yield walked_relobj
Dne pondělí 14. září 2015 11:57:05 UTC+2 Pavel S napsal(a):
>
> Hi,
>
> I just realized that I need your first solution, since I need to get only
> those objects that would cascade in case of deletion.
>
> But thanks anyhow...
>
> P
>
> Dne čtvrtek 10. září 2015 15:35:39 UTC+2 Michael Bayer napsal(a):
>>
>>
>>
>> On 9/10/15 8:48 AM, Pavel S wrote:
>>
>> Let's say, I have declarative classes A, B, C, D.
>>
>> A is the parent
>> B has FK to A
>> C has FK to B,
>> D has FK to C etc...
>>
>> I'd like to implement *generic method* walk(obj) which will recursively
>> yield dependent/related objects of obj (which is instance of A).
>>
>> I know that there is introspection interface inspect(), however I'm
>> don't really understand how to use it properly in my use case.
>>
>> Shall I do inspect(obj) or rather inspect(obj.__class__) and then
>> somehow apply inspection to obj?
>>
>> Are there an examples and best practices?
>>
>> right now you can kind of get this effect using cascade_iterator:
>> http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
>>
>> the limitation is that right now its based on relationship cascade
>> settings, as that's what it was intended for, so you'd probably want to use
>> "save-update":
>>
>> insp = inspect(my_object)
>> for obj in insp.mapper.cascade_iterator("save-update", insp):
>># ...
>>
>> to implement your own system, the graph of objects is strictly based on
>> relationship. so walk() is pretty simple:
>>
>> def walk(obj):
>> yield obj
>> insp = inspect(obj)
>> for relationship in insp.mapper.relationships:
>> related = getattr(obj, relationship.key)
>> if relationship.uselist:
>> for collection_member in related:
>> for walk_related in walk(collection_member):
>> yield walk_related
>> elif related is not None:
>> for walk_related in walk(related):
>> yield walk_related
>>
>>
>>
>>
>>
>>
>> --
>> 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+...@googlegroups.com.
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>>
>>
>>
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Re: [sqlalchemy] ORM: walk() related objects
Hi,
I just realized that I need your first solution, since I need to get only
those objects that would cascade in case of deletion.
But thanks anyhow...
P
Dne čtvrtek 10. září 2015 15:35:39 UTC+2 Michael Bayer napsal(a):
>
>
>
> On 9/10/15 8:48 AM, Pavel S wrote:
>
> Let's say, I have declarative classes A, B, C, D.
>
> A is the parent
> B has FK to A
> C has FK to B,
> D has FK to C etc...
>
> I'd like to implement *generic method* walk(obj) which will recursively
> yield dependent/related objects of obj (which is instance of A).
>
> I know that there is introspection interface inspect(), however I'm don't
> really understand how to use it properly in my use case.
>
> Shall I do inspect(obj) or rather inspect(obj.__class__) and then somehow
> apply inspection to obj?
>
> Are there an examples and best practices?
>
> right now you can kind of get this effect using cascade_iterator:
> http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
>
> the limitation is that right now its based on relationship cascade
> settings, as that's what it was intended for, so you'd probably want to use
> "save-update":
>
> insp = inspect(my_object)
> for obj in insp.mapper.cascade_iterator("save-update", insp):
># ...
>
> to implement your own system, the graph of objects is strictly based on
> relationship. so walk() is pretty simple:
>
> def walk(obj):
> yield obj
> insp = inspect(obj)
> for relationship in insp.mapper.relationships:
> related = getattr(obj, relationship.key)
> if relationship.uselist:
> for collection_member in related:
> for walk_related in walk(collection_member):
> yield walk_related
> elif related is not None:
> for walk_related in walk(related):
> yield walk_related
>
>
>
>
>
>
> --
> 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+...@googlegroups.com .
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> .
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> For more options, visit https://groups.google.com/d/optout.
>
>
>
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Re: [sqlalchemy] ORM: walk() related objects
On 9/10/15 8:48 AM, Pavel S wrote:
Let's say, I have declarative classes A, B, C, D.
A is the parent
B has FK to A
C has FK to B,
D has FK to C etc...
I'd like to implement _generic method_ walk(obj) which will
recursively yield dependent/related objects of obj (which is instance
of A).
I know that there is introspection interface inspect(), however I'm
don't really understand how to use it properly in my use case.
Shall I do inspect(obj) or rather inspect(obj.__class__) and then
somehow apply inspection to obj?
Are there an examples and best practices?
right now you can kind of get this effect using cascade_iterator:
http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
the limitation is that right now its based on relationship cascade
settings, as that's what it was intended for, so you'd probably want to
use "save-update":
insp = inspect(my_object)
for obj in insp.mapper.cascade_iterator("save-update", insp):
# ...
to implement your own system, the graph of objects is strictly based on
relationship. so walk() is pretty simple:
def walk(obj):
yield obj
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
for collection_member in related:
for walk_related in walk(collection_member):
yield walk_related
elif related is not None:
for walk_related in walk(related):
yield walk_related
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Re: [sqlalchemy] ORM: walk() related objects
Hi Michael, this is amazing, thanks!!!
On Thursday, September 10, 2015 at 3:35:39 PM UTC+2, Michael Bayer wrote:
>
>
>
> On 9/10/15 8:48 AM, Pavel S wrote:
>
> Let's say, I have declarative classes A, B, C, D.
>
> A is the parent
> B has FK to A
> C has FK to B,
> D has FK to C etc...
>
> I'd like to implement *generic method* walk(obj) which will recursively
> yield dependent/related objects of obj (which is instance of A).
>
> I know that there is introspection interface inspect(), however I'm don't
> really understand how to use it properly in my use case.
>
> Shall I do inspect(obj) or rather inspect(obj.__class__) and then somehow
> apply inspection to obj?
>
> Are there an examples and best practices?
>
> right now you can kind of get this effect using cascade_iterator:
> http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
>
> the limitation is that right now its based on relationship cascade
> settings, as that's what it was intended for, so you'd probably want to use
> "save-update":
>
> insp = inspect(my_object)
> for obj in insp.mapper.cascade_iterator("save-update", insp):
># ...
>
> to implement your own system, the graph of objects is strictly based on
> relationship. so walk() is pretty simple:
>
> def walk(obj):
> yield obj
> insp = inspect(obj)
> for relationship in insp.mapper.relationships:
> related = getattr(obj, relationship.key)
> if relationship.uselist:
> for collection_member in related:
> for walk_related in walk(collection_member):
> yield walk_related
> elif related is not None:
> for walk_related in walk(related):
> yield walk_related
>
>
>
>
>
>
> --
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> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to sqlalchemy+...@googlegroups.com .
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> .
> Visit this group at http://groups.google.com/group/sqlalchemy.
> For more options, visit https://groups.google.com/d/optout.
>
>
>
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[sqlalchemy] ORM: walk() related objects
Let's say, I have declarative classes A, B, C, D. A is the parent B has FK to A C has FK to B, D has FK to C etc... I'd like to implement *generic method* walk(obj) which will recursively yield dependent/related objects of obj (which is instance of A). I know that there is introspection interface inspect(), however I'm don't really understand how to use it properly in my use case. Shall I do inspect(obj) or rather inspect(obj.__class__) and then somehow apply inspection to obj? Are there an examples and best practices? -- 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. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
Re: [sqlalchemy] ORM: walk() related objects
On 10.9.2015 16:30, Mike Bayer wrote:
> On 9/10/15 10:26 AM, Mike Bayer wrote:
>>
>>
>> On 9/10/15 10:13 AM, Ladislav Lenart wrote:
>>> Hello.
>>>
>>> Just a really, really tiny and pedantic correction... The stack
>>> variable in the
>>> code is in fact a queue. This could potentially surprise some users /
>>> readers.
>>>
>>> To fix, please do one of the following:
>>> * Rename stack local var to queue.
>>> * Use stack.pop() to pop the last element from the stack.
>>
>> there really should be some other name, because all the time, I have
>> routines like this where even dynamically within the routine, the
>> pop(0) is a pop() or vice-versa, because we'd like the iteration to
>> work one way or another. Changing pop(0) to pop() here means we are
>> doing depth-first instead of breadth-first. So. Some word that means
>> "collection of things to operate upon"? I've seen "work" used.
>> "buffer" ? eh.
>>
>
> renamed to "deque".
Well, for me the name 'stack' automatically means depth-first whereas the name
'queue' means breadth-first. And when the name and the code do not match, I am
not sure what is the original intent. However, deque (or maybe dequeue?) is a
fine name for me.
BTW I've noticed that you use the term 'seen' for the set of already visited
objects. Perhaps you will like the name 'visit' (or 'to_visit' or
'not_visited')? At least that's what I use when I implement a visitor / iterator
pattern.
HTH,
Ladislav Lenart
>>> HTH,
>>>
>>> Ladislav Lenart
>>>
>>>
>>> On 10.9.2015 15:48, Mike Bayer wrote:
On 9/10/15 9:35 AM, Mike Bayer wrote:
>
> On 9/10/15 8:48 AM, Pavel S wrote:
>> Let's say, I have declarative classes A, B, C, D.
>>
>> A is the parent
>> B has FK to A
>> C has FK to B,
>> D has FK to C etc...
>>
>> I'd like to implement _generic method_ walk(obj) which will
>> recursively yield
>> dependent/related objects of obj (which is instance of A).
>>
>> I know that there is introspection interface inspect(), however
>> I'm don't
>> really understand how to use it properly in my use case.
>>
>> Shall I do inspect(obj) or rather inspect(obj.__class__) and then
>> somehow
>> apply inspection to obj?
>>
>> Are there an examples and best practices?
> right now you can kind of get this effect using cascade_iterator:
> http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
>
>
>
> the limitation is that right now its based on relationship cascade
> settings,
> as that's what it was intended for, so you'd probably want to use
> "save-update":
>
> insp = inspect(my_object)
> for obj in insp.mapper.cascade_iterator("save-update", insp):
> # ...
>
> to implement your own system, the graph of objects is strictly
> based on
> relationship. so walk() is pretty simple:
>
> def walk(obj):
> yield obj
> insp = inspect(obj)
> for relationship in insp.mapper.relationships:
> related = getattr(obj, relationship.key)
> if relationship.uselist:
> for collection_member in related:
> for walk_related in walk(collection_member):
> yield walk_related
> elif related is not None:
> for walk_related in walk(related):
> yield walk_related
here's one im putting in the FAQ for now, which solves recursion
depth as well
as cycles:
def walk(obj):
stack = [obj]
seen = set()
while stack:
obj = stack.pop(0)
if obj in seen:
continue
else:
seen.add(obj)
yield obj
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
stack.extend(related)
elif related is not None:
stack.append(related)
>
>
>
>
>
>> --
>> 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
>> .
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>> .
>> Visit this group at http://groups.google.com/group/sqlalchemy.
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> --
> You received this message because you are
Re: [sqlalchemy] ORM: walk() related objects
On 9/10/15 9:35 AM, Mike Bayer wrote:
On 9/10/15 8:48 AM, Pavel S wrote:
Let's say, I have declarative classes A, B, C, D.
A is the parent
B has FK to A
C has FK to B,
D has FK to C etc...
I'd like to implement _generic method_ walk(obj) which will
recursively yield dependent/related objects of obj (which is instance
of A).
I know that there is introspection interface inspect(), however I'm
don't really understand how to use it properly in my use case.
Shall I do inspect(obj) or rather inspect(obj.__class__) and then
somehow apply inspection to obj?
Are there an examples and best practices?
right now you can kind of get this effect using cascade_iterator:
http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
the limitation is that right now its based on relationship cascade
settings, as that's what it was intended for, so you'd probably want
to use "save-update":
insp = inspect(my_object)
for obj in insp.mapper.cascade_iterator("save-update", insp):
# ...
to implement your own system, the graph of objects is strictly based
on relationship. so walk() is pretty simple:
def walk(obj):
yield obj
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
for collection_member in related:
for walk_related in walk(collection_member):
yield walk_related
elif related is not None:
for walk_related in walk(related):
yield walk_related
here's one im putting in the FAQ for now, which solves recursion depth
as well as cycles:
def walk(obj):
stack = [obj]
seen = set()
while stack:
obj = stack.pop(0)
if obj in seen:
continue
else:
seen.add(obj)
yield obj
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
stack.extend(related)
elif related is not None:
stack.append(related)
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Re: [sqlalchemy] ORM: walk() related objects
On 9/10/15 10:26 AM, Mike Bayer wrote:
On 9/10/15 10:13 AM, Ladislav Lenart wrote:
Hello.
Just a really, really tiny and pedantic correction... The stack
variable in the
code is in fact a queue. This could potentially surprise some users /
readers.
To fix, please do one of the following:
* Rename stack local var to queue.
* Use stack.pop() to pop the last element from the stack.
there really should be some other name, because all the time, I have
routines like this where even dynamically within the routine, the
pop(0) is a pop() or vice-versa, because we'd like the iteration to
work one way or another. Changing pop(0) to pop() here means we are
doing depth-first instead of breadth-first. So. Some word that means
"collection of things to operate upon"? I've seen "work" used.
"buffer" ? eh.
renamed to "deque".
HTH,
Ladislav Lenart
On 10.9.2015 15:48, Mike Bayer wrote:
On 9/10/15 9:35 AM, Mike Bayer wrote:
On 9/10/15 8:48 AM, Pavel S wrote:
Let's say, I have declarative classes A, B, C, D.
A is the parent
B has FK to A
C has FK to B,
D has FK to C etc...
I'd like to implement _generic method_ walk(obj) which will
recursively yield
dependent/related objects of obj (which is instance of A).
I know that there is introspection interface inspect(), however
I'm don't
really understand how to use it properly in my use case.
Shall I do inspect(obj) or rather inspect(obj.__class__) and then
somehow
apply inspection to obj?
Are there an examples and best practices?
right now you can kind of get this effect using cascade_iterator:
http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
the limitation is that right now its based on relationship cascade
settings,
as that's what it was intended for, so you'd probably want to use
"save-update":
insp = inspect(my_object)
for obj in insp.mapper.cascade_iterator("save-update", insp):
# ...
to implement your own system, the graph of objects is strictly
based on
relationship. so walk() is pretty simple:
def walk(obj):
yield obj
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
for collection_member in related:
for walk_related in walk(collection_member):
yield walk_related
elif related is not None:
for walk_related in walk(related):
yield walk_related
here's one im putting in the FAQ for now, which solves recursion
depth as well
as cycles:
def walk(obj):
stack = [obj]
seen = set()
while stack:
obj = stack.pop(0)
if obj in seen:
continue
else:
seen.add(obj)
yield obj
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
stack.extend(related)
elif related is not None:
stack.append(related)
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To post to this
Re: [sqlalchemy] ORM: walk() related objects
Hello.
Just a really, really tiny and pedantic correction... The stack variable in the
code is in fact a queue. This could potentially surprise some users / readers.
To fix, please do one of the following:
* Rename stack local var to queue.
* Use stack.pop() to pop the last element from the stack.
HTH,
Ladislav Lenart
On 10.9.2015 15:48, Mike Bayer wrote:
>
>
> On 9/10/15 9:35 AM, Mike Bayer wrote:
>>
>>
>> On 9/10/15 8:48 AM, Pavel S wrote:
>>> Let's say, I have declarative classes A, B, C, D.
>>>
>>> A is the parent
>>> B has FK to A
>>> C has FK to B,
>>> D has FK to C etc...
>>>
>>> I'd like to implement _generic method_ walk(obj) which will recursively
>>> yield
>>> dependent/related objects of obj (which is instance of A).
>>>
>>> I know that there is introspection interface inspect(), however I'm don't
>>> really understand how to use it properly in my use case.
>>>
>>> Shall I do inspect(obj) or rather inspect(obj.__class__) and then somehow
>>> apply inspection to obj?
>>>
>>> Are there an examples and best practices?
>> right now you can kind of get this effect using cascade_iterator:
>> http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
>>
>> the limitation is that right now its based on relationship cascade settings,
>> as that's what it was intended for, so you'd probably want to use
>> "save-update":
>>
>> insp = inspect(my_object)
>> for obj in insp.mapper.cascade_iterator("save-update", insp):
>># ...
>>
>> to implement your own system, the graph of objects is strictly based on
>> relationship. so walk() is pretty simple:
>>
>> def walk(obj):
>> yield obj
>> insp = inspect(obj)
>> for relationship in insp.mapper.relationships:
>> related = getattr(obj, relationship.key)
>> if relationship.uselist:
>> for collection_member in related:
>> for walk_related in walk(collection_member):
>> yield walk_related
>> elif related is not None:
>> for walk_related in walk(related):
>> yield walk_related
>
> here's one im putting in the FAQ for now, which solves recursion depth as well
> as cycles:
>
> def walk(obj):
> stack = [obj]
>
> seen = set()
>
> while stack:
> obj = stack.pop(0)
> if obj in seen:
> continue
> else:
> seen.add(obj)
> yield obj
> insp = inspect(obj)
> for relationship in insp.mapper.relationships:
> related = getattr(obj, relationship.key)
> if relationship.uselist:
> stack.extend(related)
> elif related is not None:
> stack.append(related)
>
>
>
>
>>
>>
>>
>>
>>
>>
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Re: [sqlalchemy] ORM: walk() related objects
In the meanwhile, I've implemented similar:
def walk(obj, level=0, memo=None):
memo = memo or set()
if obj not in memo:
yield level, obj
memo.add(obj)
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
for collection_member in related:
for walk_related in walk(collection_member, level + 1,
memo):
yield walk_related
elif related is not None:
for walk_related in walk(related, level + 1, memo):
yield walk_related
On Thursday, September 10, 2015 at 3:48:55 PM UTC+2, Michael Bayer wrote:
>
>
>
> On 9/10/15 9:35 AM, Mike Bayer wrote:
>
>
>
> On 9/10/15 8:48 AM, Pavel S wrote:
>
> Let's say, I have declarative classes A, B, C, D.
>
> A is the parent
> B has FK to A
> C has FK to B,
> D has FK to C etc...
>
> I'd like to implement *generic method* walk(obj) which will recursively
> yield dependent/related objects of obj (which is instance of A).
>
> I know that there is introspection interface inspect(), however I'm don't
> really understand how to use it properly in my use case.
>
> Shall I do inspect(obj) or rather inspect(obj.__class__) and then somehow
> apply inspection to obj?
>
> Are there an examples and best practices?
>
> right now you can kind of get this effect using cascade_iterator:
> http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
>
> the limitation is that right now its based on relationship cascade
> settings, as that's what it was intended for, so you'd probably want to use
> "save-update":
>
> insp = inspect(my_object)
> for obj in insp.mapper.cascade_iterator("save-update", insp):
># ...
>
> to implement your own system, the graph of objects is strictly based on
> relationship. so walk() is pretty simple:
>
> def walk(obj):
> yield obj
> insp = inspect(obj)
> for relationship in insp.mapper.relationships:
> related = getattr(obj, relationship.key)
> if relationship.uselist:
> for collection_member in related:
> for walk_related in walk(collection_member):
> yield walk_related
> elif related is not None:
> for walk_related in walk(related):
> yield walk_related
>
>
> here's one im putting in the FAQ for now, which solves recursion depth as
> well as cycles:
>
> def walk(obj):
> stack = [obj]
>
> seen = set()
>
> while stack:
> obj = stack.pop(0)
> if obj in seen:
> continue
> else:
> seen.add(obj)
> yield obj
> insp = inspect(obj)
> for relationship in insp.mapper.relationships:
> related = getattr(obj, relationship.key)
> if relationship.uselist:
> stack.extend(related)
> elif related is not None:
> stack.append(related)
>
>
>
>
>
>
>
>
>
>
> --
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> email to sqlalchemy+...@googlegroups.com .
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Re: [sqlalchemy] ORM: walk() related objects
On 9/10/15 10:13 AM, Ladislav Lenart wrote:
Hello.
Just a really, really tiny and pedantic correction... The stack variable in the
code is in fact a queue. This could potentially surprise some users / readers.
To fix, please do one of the following:
* Rename stack local var to queue.
* Use stack.pop() to pop the last element from the stack.
there really should be some other name, because all the time, I have
routines like this where even dynamically within the routine, the pop(0)
is a pop() or vice-versa, because we'd like the iteration to work one
way or another. Changing pop(0) to pop() here means we are doing
depth-first instead of breadth-first. So. Some word that means
"collection of things to operate upon"? I've seen "work" used.
"buffer" ? eh.
HTH,
Ladislav Lenart
On 10.9.2015 15:48, Mike Bayer wrote:
On 9/10/15 9:35 AM, Mike Bayer wrote:
On 9/10/15 8:48 AM, Pavel S wrote:
Let's say, I have declarative classes A, B, C, D.
A is the parent
B has FK to A
C has FK to B,
D has FK to C etc...
I'd like to implement _generic method_ walk(obj) which will recursively yield
dependent/related objects of obj (which is instance of A).
I know that there is introspection interface inspect(), however I'm don't
really understand how to use it properly in my use case.
Shall I do inspect(obj) or rather inspect(obj.__class__) and then somehow
apply inspection to obj?
Are there an examples and best practices?
right now you can kind of get this effect using cascade_iterator:
http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator
the limitation is that right now its based on relationship cascade settings,
as that's what it was intended for, so you'd probably want to use "save-update":
insp = inspect(my_object)
for obj in insp.mapper.cascade_iterator("save-update", insp):
# ...
to implement your own system, the graph of objects is strictly based on
relationship. so walk() is pretty simple:
def walk(obj):
yield obj
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
for collection_member in related:
for walk_related in walk(collection_member):
yield walk_related
elif related is not None:
for walk_related in walk(related):
yield walk_related
here's one im putting in the FAQ for now, which solves recursion depth as well
as cycles:
def walk(obj):
stack = [obj]
seen = set()
while stack:
obj = stack.pop(0)
if obj in seen:
continue
else:
seen.add(obj)
yield obj
insp = inspect(obj)
for relationship in insp.mapper.relationships:
related = getattr(obj, relationship.key)
if relationship.uselist:
stack.extend(related)
elif related is not None:
stack.append(related)
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