[web2py] Re: Newbie: Cascading deletes with SQLFORM.grid and GAE
Aha!! I don't know how I missed that before but indeed the event was
throwing an exception and GAE kept on going on its merry way. Found a
couple of things I was doing wrong. The delete event method takes only one
parameter (the query) and once you get the query you can do a straight
'select()' from that and figure out which ID's are being deleted.
Thanks so much for the help!! I appreciate the guidance and coaching.
On Tuesday, November 27, 2012 10:39:54 AM UTC-6, howesc wrote:
>
> Julian,
>
> can you add logging to your delete_linked method to prove to yourself that
> it is being called, and that it is not throwing an exception? that will
> help us track down where it's gone astray
>
> thanks!
>
> cfh
>
> On Sunday, November 25, 2012 5:43:16 PM UTC-8, Julian Sanchez wrote:
>>
>> Oh, I see. I thought that were you mentioned logs you were referring to
>> the built-in logs inside web2py (I assume there are some?). As far as my
>> 'test app' is concerned all there is is the code I posted a couple of posts
>> ago. I also added these controllers for testing the deletion of records:
>>
>> def phones():
>> form = SQLFORM.grid(query=(db.phone.id > 0))
>> return dict(form=form)
>>
>> def carriers():
>> form = SQLFORM.grid(query=(db.carrier.id > 0))
>> return dict(form=form)
>>
>> def manufacturers():
>> form = SQLFORM.grid(query=(db.manufacturer.id > 0))
>> return dict(form=form)
>>
>>
>> All I do is invoke those controllers, add a couple of test entries, and
>> then delete a carrier that is being referenced by a couple of phones. With
>> the _before_delete even nothing gets deleted and nothing special is shown
>> in the GAE console. That's what puzzling me.
>>
>>
>>
>> On Sunday, November 25, 2012 12:13:41 AM UTC-6, howesc wrote:
>>>
>>> honestly, i'm not smart enough to use logging.conf. i'm not sure how
>>> much of it is GAE overriding things, and how much of it is my inability to
>>> read the docs and understand how it works! anyhow, i don't have a
>>> logging.conf in my GAE setups, but i use logging extensively and it all
>>> seems to show up in the GAE console logs just fine.
>>>
>>> if you have no logging.conf and you have logging.info statements in
>>> your code, can you find the messages in your logs?
>>>
>>> cfh
>>>
>>> On Saturday, November 24, 2012 5:29:41 AM UTC-8, Julian Sanchez wrote:
Are there any specific things I need to do to enable logging under GAE?
This is what I did:
- renamed the logging.example.conf file to logging.conf
- added an entry for the test app I created above
- removed all references to all handlers except consoleHandler
Any page I request gives me an "IOError: invalid mode: a" in the GAE
logging console. If I renamed the logging file back to
logging.example.conf then I can request pages and run the app just fine.
On Friday, November 23, 2012 7:47:26 PM UTC-6, howesc wrote:
>
> can you add some logging in and let us know if there are exceptions?
>
> about the delete limitations - web2py iterates over the set of items
> to delete and deletes them (the version in trunk is improved over the
> last
> release, but both still work). if the set of items to delete is large
> the
> query to get the items to delete may take too long and timeout. in the
> latest released version it actually can timeout before any rows are
> deleted. in the trunk version it will delete at least some rows before
> the
> first timeout (in most cases), so over a series of retries all the rows
> will be deleted. This behavior is all to deal with how GAE implements
> delete, so it is GAE specific.
>
> cfh
>
>
> On Wednesday, November 21, 2012 5:04:32 PM UTC-8, Julian Sanchez wrote:
>>
>> Massimo,
>>
>> I created a small test to try your function:
>>
>> db.define_table('carrier',
>> Field('name', type='string'),
>> Field('description', type='string')
>>)
>>
>> db.carrier.name.requires = IS_NOT_IN_DB(db(db.carrier.id > 0), '
>> carrier.name')
>>
>> db.define_table('manufacturer',
>> Field('name', type='string'),
>> Field('country', type='string')
>>)
>>
>>
>> db.manufacturer.name.requires = IS_NOT_IN_DB(db(db.manufacturer.id >
>> 0), 'manufacturer.name')
>>
>> db.define_table('phone',
>> Field('model', type='string'),
>> Field('manufacturer', db.manufacturer),
>> Field('carrier', db.carrier)
>>)
>>
>> db.phone.manufacturer.requires = IS_IN_DB(db, 'manufacturer.id',
>> '%(name)s
[web2py] Re: Newbie: Cascading deletes with SQLFORM.grid and GAE
Julian,
can you add logging to your delete_linked method to prove to yourself that
it is being called, and that it is not throwing an exception? that will
help us track down where it's gone astray
thanks!
cfh
On Sunday, November 25, 2012 5:43:16 PM UTC-8, Julian Sanchez wrote:
>
> Oh, I see. I thought that were you mentioned logs you were referring to
> the built-in logs inside web2py (I assume there are some?). As far as my
> 'test app' is concerned all there is is the code I posted a couple of posts
> ago. I also added these controllers for testing the deletion of records:
>
> def phones():
> form = SQLFORM.grid(query=(db.phone.id > 0))
> return dict(form=form)
>
> def carriers():
> form = SQLFORM.grid(query=(db.carrier.id > 0))
> return dict(form=form)
>
> def manufacturers():
> form = SQLFORM.grid(query=(db.manufacturer.id > 0))
> return dict(form=form)
>
>
> All I do is invoke those controllers, add a couple of test entries, and
> then delete a carrier that is being referenced by a couple of phones. With
> the _before_delete even nothing gets deleted and nothing special is shown
> in the GAE console. That's what puzzling me.
>
>
>
> On Sunday, November 25, 2012 12:13:41 AM UTC-6, howesc wrote:
>>
>> honestly, i'm not smart enough to use logging.conf. i'm not sure how
>> much of it is GAE overriding things, and how much of it is my inability to
>> read the docs and understand how it works! anyhow, i don't have a
>> logging.conf in my GAE setups, but i use logging extensively and it all
>> seems to show up in the GAE console logs just fine.
>>
>> if you have no logging.conf and you have logging.info statements in your
>> code, can you find the messages in your logs?
>>
>> cfh
>>
>> On Saturday, November 24, 2012 5:29:41 AM UTC-8, Julian Sanchez wrote:
>>>
>>> Are there any specific things I need to do to enable logging under GAE?
>>> This is what I did:
>>>
>>>- renamed the logging.example.conf file to logging.conf
>>>- added an entry for the test app I created above
>>>- removed all references to all handlers except consoleHandler
>>>
>>> Any page I request gives me an "IOError: invalid mode: a" in the GAE
>>> logging console. If I renamed the logging file back to
>>> logging.example.conf then I can request pages and run the app just fine.
>>>
>>> On Friday, November 23, 2012 7:47:26 PM UTC-6, howesc wrote:
can you add some logging in and let us know if there are exceptions?
about the delete limitations - web2py iterates over the set of items to
delete and deletes them (the version in trunk is improved over the last
release, but both still work). if the set of items to delete is large the
query to get the items to delete may take too long and timeout. in the
latest released version it actually can timeout before any rows are
deleted. in the trunk version it will delete at least some rows before
the
first timeout (in most cases), so over a series of retries all the rows
will be deleted. This behavior is all to deal with how GAE implements
delete, so it is GAE specific.
cfh
On Wednesday, November 21, 2012 5:04:32 PM UTC-8, Julian Sanchez wrote:
>
> Massimo,
>
> I created a small test to try your function:
>
> db.define_table('carrier',
> Field('name', type='string'),
> Field('description', type='string')
>)
>
> db.carrier.name.requires = IS_NOT_IN_DB(db(db.carrier.id > 0), '
> carrier.name')
>
> db.define_table('manufacturer',
> Field('name', type='string'),
> Field('country', type='string')
>)
>
>
> db.manufacturer.name.requires = IS_NOT_IN_DB(db(db.manufacturer.id > 0
> ), 'manufacturer.name')
>
> db.define_table('phone',
> Field('model', type='string'),
> Field('manufacturer', db.manufacturer),
> Field('carrier', db.carrier)
>)
>
> db.phone.manufacturer.requires = IS_IN_DB(db, 'manufacturer.id',
> '%(name)s')
> db.phone.carrier.requires = IS_IN_DB(db, 'carrier.id', '%(name)s')
>
>
>
>
> def delete_linked(query, table=db.carrier):
> ids = [t.id in db(query).select(db.table.id)]
> for field in table._referenced_by:
> db(field._table._id.belongs(ids)).delete()
>
>
> db.carrier._before_delete.append(delete_linked)
>
> I can create an Apple iPhone on Verizon and an Apple iPhone on Sprint.
> If I run this under sqlite and I delete the carrier 'Sprint' I see one
> of
> the phones deleted as well (even without the '_before_delete' event which
[web2py] Re: Newbie: Cascading deletes with SQLFORM.grid and GAE
Oh, I see. I thought that were you mentioned logs you were referring to
the built-in logs inside web2py (I assume there are some?). As far as my
'test app' is concerned all there is is the code I posted a couple of posts
ago. I also added these controllers for testing the deletion of records:
def phones():
form = SQLFORM.grid(query=(db.phone.id > 0))
return dict(form=form)
def carriers():
form = SQLFORM.grid(query=(db.carrier.id > 0))
return dict(form=form)
def manufacturers():
form = SQLFORM.grid(query=(db.manufacturer.id > 0))
return dict(form=form)
All I do is invoke those controllers, add a couple of test entries, and
then delete a carrier that is being referenced by a couple of phones. With
the _before_delete even nothing gets deleted and nothing special is shown
in the GAE console. That's what puzzling me.
On Sunday, November 25, 2012 12:13:41 AM UTC-6, howesc wrote:
>
> honestly, i'm not smart enough to use logging.conf. i'm not sure how much
> of it is GAE overriding things, and how much of it is my inability to read
> the docs and understand how it works! anyhow, i don't have a logging.conf
> in my GAE setups, but i use logging extensively and it all seems to show up
> in the GAE console logs just fine.
>
> if you have no logging.conf and you have logging.info statements in your
> code, can you find the messages in your logs?
>
> cfh
>
> On Saturday, November 24, 2012 5:29:41 AM UTC-8, Julian Sanchez wrote:
>>
>> Are there any specific things I need to do to enable logging under GAE?
>> This is what I did:
>>
>>- renamed the logging.example.conf file to logging.conf
>>- added an entry for the test app I created above
>>- removed all references to all handlers except consoleHandler
>>
>> Any page I request gives me an "IOError: invalid mode: a" in the GAE
>> logging console. If I renamed the logging file back to
>> logging.example.conf then I can request pages and run the app just fine.
>>
>> On Friday, November 23, 2012 7:47:26 PM UTC-6, howesc wrote:
>>>
>>> can you add some logging in and let us know if there are exceptions?
>>>
>>> about the delete limitations - web2py iterates over the set of items to
>>> delete and deletes them (the version in trunk is improved over the last
>>> release, but both still work). if the set of items to delete is large the
>>> query to get the items to delete may take too long and timeout. in the
>>> latest released version it actually can timeout before any rows are
>>> deleted. in the trunk version it will delete at least some rows before the
>>> first timeout (in most cases), so over a series of retries all the rows
>>> will be deleted. This behavior is all to deal with how GAE implements
>>> delete, so it is GAE specific.
>>>
>>> cfh
>>>
>>>
>>> On Wednesday, November 21, 2012 5:04:32 PM UTC-8, Julian Sanchez wrote:
Massimo,
I created a small test to try your function:
db.define_table('carrier',
Field('name', type='string'),
Field('description', type='string')
)
db.carrier.name.requires = IS_NOT_IN_DB(db(db.carrier.id > 0), '
carrier.name')
db.define_table('manufacturer',
Field('name', type='string'),
Field('country', type='string')
)
db.manufacturer.name.requires = IS_NOT_IN_DB(db(db.manufacturer.id > 0
), 'manufacturer.name')
db.define_table('phone',
Field('model', type='string'),
Field('manufacturer', db.manufacturer),
Field('carrier', db.carrier)
)
db.phone.manufacturer.requires = IS_IN_DB(db, 'manufacturer.id',
'%(name)s')
db.phone.carrier.requires = IS_IN_DB(db, 'carrier.id', '%(name)s')
def delete_linked(query, table=db.carrier):
ids = [t.id in db(query).select(db.table.id)]
for field in table._referenced_by:
db(field._table._id.belongs(ids)).delete()
db.carrier._before_delete.append(delete_linked)
I can create an Apple iPhone on Verizon and an Apple iPhone on Sprint.
If I run this under sqlite and I delete the carrier 'Sprint' I see one of
the phones deleted as well (even without the '_before_delete' event which
makes sense since that's the default behavior).
However if I run this under GAE:
- Without the '_before_delete' event the carrier 'Sprint' is
deleted but not the phone. This is expected since cascading doesn't
work.
- With the '_before_delete' event (code just as above) *nothing*gets
deleted, not even the carrier. I can see it disappear from the list
but if I refresh the p
[web2py] Re: Newbie: Cascading deletes with SQLFORM.grid and GAE
honestly, i'm not smart enough to use logging.conf. i'm not sure how much
of it is GAE overriding things, and how much of it is my inability to read
the docs and understand how it works! anyhow, i don't have a logging.conf
in my GAE setups, but i use logging extensively and it all seems to show up
in the GAE console logs just fine.
if you have no logging.conf and you have logging.info statements in your
code, can you find the messages in your logs?
cfh
On Saturday, November 24, 2012 5:29:41 AM UTC-8, Julian Sanchez wrote:
>
> Are there any specific things I need to do to enable logging under GAE?
> This is what I did:
>
>- renamed the logging.example.conf file to logging.conf
>- added an entry for the test app I created above
>- removed all references to all handlers except consoleHandler
>
> Any page I request gives me an "IOError: invalid mode: a" in the GAE
> logging console. If I renamed the logging file back to
> logging.example.conf then I can request pages and run the app just fine.
>
> On Friday, November 23, 2012 7:47:26 PM UTC-6, howesc wrote:
>>
>> can you add some logging in and let us know if there are exceptions?
>>
>> about the delete limitations - web2py iterates over the set of items to
>> delete and deletes them (the version in trunk is improved over the last
>> release, but both still work). if the set of items to delete is large the
>> query to get the items to delete may take too long and timeout. in the
>> latest released version it actually can timeout before any rows are
>> deleted. in the trunk version it will delete at least some rows before the
>> first timeout (in most cases), so over a series of retries all the rows
>> will be deleted. This behavior is all to deal with how GAE implements
>> delete, so it is GAE specific.
>>
>> cfh
>>
>>
>> On Wednesday, November 21, 2012 5:04:32 PM UTC-8, Julian Sanchez wrote:
>>>
>>> Massimo,
>>>
>>> I created a small test to try your function:
>>>
>>> db.define_table('carrier',
>>> Field('name', type='string'),
>>> Field('description', type='string')
>>>)
>>>
>>> db.carrier.name.requires = IS_NOT_IN_DB(db(db.carrier.id > 0), '
>>> carrier.name')
>>>
>>> db.define_table('manufacturer',
>>> Field('name', type='string'),
>>> Field('country', type='string')
>>>)
>>>
>>>
>>> db.manufacturer.name.requires = IS_NOT_IN_DB(db(db.manufacturer.id > 0),
>>> 'manufacturer.name')
>>>
>>> db.define_table('phone',
>>> Field('model', type='string'),
>>> Field('manufacturer', db.manufacturer),
>>> Field('carrier', db.carrier)
>>>)
>>>
>>> db.phone.manufacturer.requires = IS_IN_DB(db, 'manufacturer.id',
>>> '%(name)s')
>>> db.phone.carrier.requires = IS_IN_DB(db, 'carrier.id', '%(name)s')
>>>
>>>
>>>
>>>
>>> def delete_linked(query, table=db.carrier):
>>> ids = [t.id in db(query).select(db.table.id)]
>>> for field in table._referenced_by:
>>> db(field._table._id.belongs(ids)).delete()
>>>
>>>
>>> db.carrier._before_delete.append(delete_linked)
>>>
>>> I can create an Apple iPhone on Verizon and an Apple iPhone on Sprint.
>>> If I run this under sqlite and I delete the carrier 'Sprint' I see one of
>>> the phones deleted as well (even without the '_before_delete' event which
>>> makes sense since that's the default behavior).
>>> However if I run this under GAE:
>>>
>>>- Without the '_before_delete' event the carrier 'Sprint' is deleted
>>>but not the phone. This is expected since cascading doesn't work.
>>>- With the '_before_delete' event (code just as above) *nothing*gets
>>> deleted, not even the carrier. I can see it disappear from the list
>>>but if I refresh the page it comes right back. I can also verify the
>>>record is still there by looking at the GAE admin page (Datastore
>>> viewer).
>>> Also, none of the phones are deleted either.
>>>
>>> Am I missing something?
>>>
>>> Also, when you say that if I delete too many records the operation may
>>> fail midway... is that a GAE limitation? Is the 1000 record limit I've
>>> read somewhere about?
>>>
>>> Thanks,
>>> Julian
>>>
>>> On Saturday, November 17, 2012 1:06:01 PM UTC-6, Massimo Di Pierro wrote:
You can try something like
def delete_linked(query, table=table):
ids = [t.id in db(query).select(db.table.id)]
for field in table._referenced_by:
db(field._table._id.belongs(ids)).delete()
db.table._before_delete.append(delete_linked)
but you will run into consistency problems. If there are too many
records this may fail midway.
On Wednesday, 14 November 2012 19:07:02 UTC-6, Julian Sanchez wrote:
>
> Hi Everyone!! Long time lurker
[web2py] Re: Newbie: Cascading deletes with SQLFORM.grid and GAE
Are there any specific things I need to do to enable logging under GAE?
This is what I did:
- renamed the logging.example.conf file to logging.conf
- added an entry for the test app I created above
- removed all references to all handlers except consoleHandler
Any page I request gives me an "IOError: invalid mode: a" in the GAE
logging console. If I renamed the logging file back to
logging.example.conf then I can request pages and run the app just fine.
On Friday, November 23, 2012 7:47:26 PM UTC-6, howesc wrote:
>
> can you add some logging in and let us know if there are exceptions?
>
> about the delete limitations - web2py iterates over the set of items to
> delete and deletes them (the version in trunk is improved over the last
> release, but both still work). if the set of items to delete is large the
> query to get the items to delete may take too long and timeout. in the
> latest released version it actually can timeout before any rows are
> deleted. in the trunk version it will delete at least some rows before the
> first timeout (in most cases), so over a series of retries all the rows
> will be deleted. This behavior is all to deal with how GAE implements
> delete, so it is GAE specific.
>
> cfh
>
>
> On Wednesday, November 21, 2012 5:04:32 PM UTC-8, Julian Sanchez wrote:
>>
>> Massimo,
>>
>> I created a small test to try your function:
>>
>> db.define_table('carrier',
>> Field('name', type='string'),
>> Field('description', type='string')
>>)
>>
>> db.carrier.name.requires = IS_NOT_IN_DB(db(db.carrier.id > 0), '
>> carrier.name')
>>
>> db.define_table('manufacturer',
>> Field('name', type='string'),
>> Field('country', type='string')
>>)
>>
>>
>> db.manufacturer.name.requires = IS_NOT_IN_DB(db(db.manufacturer.id > 0),
>> 'manufacturer.name')
>>
>> db.define_table('phone',
>> Field('model', type='string'),
>> Field('manufacturer', db.manufacturer),
>> Field('carrier', db.carrier)
>>)
>>
>> db.phone.manufacturer.requires = IS_IN_DB(db, 'manufacturer.id',
>> '%(name)s')
>> db.phone.carrier.requires = IS_IN_DB(db, 'carrier.id', '%(name)s')
>>
>>
>>
>>
>> def delete_linked(query, table=db.carrier):
>> ids = [t.id in db(query).select(db.table.id)]
>> for field in table._referenced_by:
>> db(field._table._id.belongs(ids)).delete()
>>
>>
>> db.carrier._before_delete.append(delete_linked)
>>
>> I can create an Apple iPhone on Verizon and an Apple iPhone on Sprint.
>> If I run this under sqlite and I delete the carrier 'Sprint' I see one of
>> the phones deleted as well (even without the '_before_delete' event which
>> makes sense since that's the default behavior).
>> However if I run this under GAE:
>>
>>- Without the '_before_delete' event the carrier 'Sprint' is deleted
>>but not the phone. This is expected since cascading doesn't work.
>>- With the '_before_delete' event (code just as above) *nothing* gets
>>deleted, not even the carrier. I can see it disappear from the list but
>> if
>>I refresh the page it comes right back. I can also verify the record is
>>still there by looking at the GAE admin page (Datastore viewer). Also,
>>none of the phones are deleted either.
>>
>> Am I missing something?
>>
>> Also, when you say that if I delete too many records the operation may
>> fail midway... is that a GAE limitation? Is the 1000 record limit I've
>> read somewhere about?
>>
>> Thanks,
>> Julian
>>
>> On Saturday, November 17, 2012 1:06:01 PM UTC-6, Massimo Di Pierro wrote:
>>>
>>> You can try something like
>>>
>>> def delete_linked(query, table=table):
>>> ids = [t.id in db(query).select(db.table.id)]
>>> for field in table._referenced_by:
>>> db(field._table._id.belongs(ids)).delete()
>>>
>>> db.table._before_delete.append(delete_linked)
>>>
>>> but you will run into consistency problems. If there are too many
>>> records this may fail midway.
>>>
>>> On Wednesday, 14 November 2012 19:07:02 UTC-6, Julian Sanchez wrote:
Hi Everyone!! Long time lurker & first time posting...
I am working on a simple application that I intend to deploy in GAE. I
have a few tables with fields that reference other tables which by default
enables the ondelete=CASCADE behavior. This works fine when I run the app
locally using sqlite as the database.
I believe GAE doesn't support cascading deletes natively.
I presume web2py doesn't support cascading deletes when running under
GAE because I don't see that happening. When I delete a row (rendered
through SQLFORM.grid) only that row is deleted an all dependent tables
remain untouched.
The problem I have
[web2py] Re: Newbie: Cascading deletes with SQLFORM.grid and GAE
can you add some logging in and let us know if there are exceptions?
about the delete limitations - web2py iterates over the set of items to
delete and deletes them (the version in trunk is improved over the last
release, but both still work). if the set of items to delete is large the
query to get the items to delete may take too long and timeout. in the
latest released version it actually can timeout before any rows are
deleted. in the trunk version it will delete at least some rows before the
first timeout (in most cases), so over a series of retries all the rows
will be deleted. This behavior is all to deal with how GAE implements
delete, so it is GAE specific.
cfh
On Wednesday, November 21, 2012 5:04:32 PM UTC-8, Julian Sanchez wrote:
>
> Massimo,
>
> I created a small test to try your function:
>
> db.define_table('carrier',
> Field('name', type='string'),
> Field('description', type='string')
>)
>
> db.carrier.name.requires = IS_NOT_IN_DB(db(db.carrier.id > 0), '
> carrier.name')
>
> db.define_table('manufacturer',
> Field('name', type='string'),
> Field('country', type='string')
>)
>
>
> db.manufacturer.name.requires = IS_NOT_IN_DB(db(db.manufacturer.id > 0), '
> manufacturer.name')
>
> db.define_table('phone',
> Field('model', type='string'),
> Field('manufacturer', db.manufacturer),
> Field('carrier', db.carrier)
>)
>
> db.phone.manufacturer.requires = IS_IN_DB(db, 'manufacturer.id',
> '%(name)s')
> db.phone.carrier.requires = IS_IN_DB(db, 'carrier.id', '%(name)s')
>
>
>
>
> def delete_linked(query, table=db.carrier):
> ids = [t.id in db(query).select(db.table.id)]
> for field in table._referenced_by:
> db(field._table._id.belongs(ids)).delete()
>
>
> db.carrier._before_delete.append(delete_linked)
>
> I can create an Apple iPhone on Verizon and an Apple iPhone on Sprint. If
> I run this under sqlite and I delete the carrier 'Sprint' I see one of the
> phones deleted as well (even without the '_before_delete' event which makes
> sense since that's the default behavior).
> However if I run this under GAE:
>
>- Without the '_before_delete' event the carrier 'Sprint' is deleted
>but not the phone. This is expected since cascading doesn't work.
>- With the '_before_delete' event (code just as above) *nothing* gets
>deleted, not even the carrier. I can see it disappear from the list but
> if
>I refresh the page it comes right back. I can also verify the record is
>still there by looking at the GAE admin page (Datastore viewer). Also,
>none of the phones are deleted either.
>
> Am I missing something?
>
> Also, when you say that if I delete too many records the operation may
> fail midway... is that a GAE limitation? Is the 1000 record limit I've
> read somewhere about?
>
> Thanks,
> Julian
>
> On Saturday, November 17, 2012 1:06:01 PM UTC-6, Massimo Di Pierro wrote:
>>
>> You can try something like
>>
>> def delete_linked(query, table=table):
>> ids = [t.id in db(query).select(db.table.id)]
>> for field in table._referenced_by:
>> db(field._table._id.belongs(ids)).delete()
>>
>> db.table._before_delete.append(delete_linked)
>>
>> but you will run into consistency problems. If there are too many records
>> this may fail midway.
>>
>> On Wednesday, 14 November 2012 19:07:02 UTC-6, Julian Sanchez wrote:
>>>
>>> Hi Everyone!! Long time lurker & first time posting...
>>>
>>> I am working on a simple application that I intend to deploy in GAE. I
>>> have a few tables with fields that reference other tables which by default
>>> enables the ondelete=CASCADE behavior. This works fine when I run the app
>>> locally using sqlite as the database.
>>> I believe GAE doesn't support cascading deletes natively.
>>> I presume web2py doesn't support cascading deletes when running under
>>> GAE because I don't see that happening. When I delete a row (rendered
>>> through SQLFORM.grid) only that row is deleted an all dependent tables
>>> remain untouched.
>>>
>>> The problem I have is that I can't find a way for me to implement the
>>> cascading behavior manually. I added a 'ondelete=mydelete' event for the
>>> SQLFORM.grid where I do the manual delete of the dependent tables and
>>> commit in the database, but that doesn't seem to work either. I searched
>>> through this forum but didn't find any suggestions either. Any suggestions
>>> as to what could I do to solve this?? Do I have to stay away from
>>> SQLFORM.grid to avoid this problem?
>>>
>>> Many Thanks!!
>>> Julian
>>>
>>> I am using web2py Version 2.2.1 (2012-10-21 16:57:04) stable on OS X
>>> Mountain Lion and GoogleAppEngineLauncher version 1.7.3 (1.7.3.333)
>
[web2py] Re: Newbie: Cascading deletes with SQLFORM.grid and GAE
Massimo,
I created a small test to try your function:
db.define_table('carrier',
Field('name', type='string'),
Field('description', type='string')
)
db.carrier.name.requires = IS_NOT_IN_DB(db(db.carrier.id > 0),
'carrier.name')
db.define_table('manufacturer',
Field('name', type='string'),
Field('country', type='string')
)
db.manufacturer.name.requires = IS_NOT_IN_DB(db(db.manufacturer.id > 0),
'manufacturer.name')
db.define_table('phone',
Field('model', type='string'),
Field('manufacturer', db.manufacturer),
Field('carrier', db.carrier)
)
db.phone.manufacturer.requires = IS_IN_DB(db, 'manufacturer.id', '%(name)s')
db.phone.carrier.requires = IS_IN_DB(db, 'carrier.id', '%(name)s')
def delete_linked(query, table=db.carrier):
ids = [t.id in db(query).select(db.table.id)]
for field in table._referenced_by:
db(field._table._id.belongs(ids)).delete()
db.carrier._before_delete.append(delete_linked)
I can create an Apple iPhone on Verizon and an Apple iPhone on Sprint. If
I run this under sqlite and I delete the carrier 'Sprint' I see one of the
phones deleted as well (even without the '_before_delete' event which makes
sense since that's the default behavior).
However if I run this under GAE:
- Without the '_before_delete' event the carrier 'Sprint' is deleted but
not the phone. This is expected since cascading doesn't work.
- With the '_before_delete' event (code just as above) *nothing* gets
deleted, not even the carrier. I can see it disappear from the list but if
I refresh the page it comes right back. I can also verify the record is
still there by looking at the GAE admin page (Datastore viewer). Also,
none of the phones are deleted either.
Am I missing something?
Also, when you say that if I delete too many records the operation may fail
midway... is that a GAE limitation? Is the 1000 record limit I've read
somewhere about?
Thanks,
Julian
On Saturday, November 17, 2012 1:06:01 PM UTC-6, Massimo Di Pierro wrote:
>
> You can try something like
>
> def delete_linked(query, table=table):
> ids = [t.id in db(query).select(db.table.id)]
> for field in table._referenced_by:
> db(field._table._id.belongs(ids)).delete()
>
> db.table._before_delete.append(delete_linked)
>
> but you will run into consistency problems. If there are too many records
> this may fail midway.
>
> On Wednesday, 14 November 2012 19:07:02 UTC-6, Julian Sanchez wrote:
>>
>> Hi Everyone!! Long time lurker & first time posting...
>>
>> I am working on a simple application that I intend to deploy in GAE. I
>> have a few tables with fields that reference other tables which by default
>> enables the ondelete=CASCADE behavior. This works fine when I run the app
>> locally using sqlite as the database.
>> I believe GAE doesn't support cascading deletes natively.
>> I presume web2py doesn't support cascading deletes when running under GAE
>> because I don't see that happening. When I delete a row (rendered through
>> SQLFORM.grid) only that row is deleted an all dependent tables remain
>> untouched.
>>
>> The problem I have is that I can't find a way for me to implement the
>> cascading behavior manually. I added a 'ondelete=mydelete' event for the
>> SQLFORM.grid where I do the manual delete of the dependent tables and
>> commit in the database, but that doesn't seem to work either. I searched
>> through this forum but didn't find any suggestions either. Any suggestions
>> as to what could I do to solve this?? Do I have to stay away from
>> SQLFORM.grid to avoid this problem?
>>
>> Many Thanks!!
>> Julian
>>
>> I am using web2py Version 2.2.1 (2012-10-21 16:57:04) stable on OS X
>> Mountain Lion and GoogleAppEngineLauncher version 1.7.3 (1.7.3.333)
>>
>
--
[web2py] Re: Newbie: Cascading deletes with SQLFORM.grid and GAE
You can try something like def delete_linked(query, table=table): ids = [t.id in db(query).select(db.table.id)] for field in table._referenced_by: db(field._table._id.belongs(ids)).delete() db.table._before_delete.append(delete_linked) but you will run into consistency problems. If there are too many records this may fail midway. On Wednesday, 14 November 2012 19:07:02 UTC-6, Julian Sanchez wrote: > > Hi Everyone!! Long time lurker & first time posting... > > I am working on a simple application that I intend to deploy in GAE. I > have a few tables with fields that reference other tables which by default > enables the ondelete=CASCADE behavior. This works fine when I run the app > locally using sqlite as the database. > I believe GAE doesn't support cascading deletes natively. > I presume web2py doesn't support cascading deletes when running under GAE > because I don't see that happening. When I delete a row (rendered through > SQLFORM.grid) only that row is deleted an all dependent tables remain > untouched. > > The problem I have is that I can't find a way for me to implement the > cascading behavior manually. I added a 'ondelete=mydelete' event for the > SQLFORM.grid where I do the manual delete of the dependent tables and > commit in the database, but that doesn't seem to work either. I searched > through this forum but didn't find any suggestions either. Any suggestions > as to what could I do to solve this?? Do I have to stay away from > SQLFORM.grid to avoid this problem? > > Many Thanks!! > Julian > > I am using web2py Version 2.2.1 (2012-10-21 16:57:04) stable on OS X > Mountain Lion and GoogleAppEngineLauncher version 1.7.3 (1.7.3.333) > --
