on_define was specifically created to keep lazy tables lazy. If lazy tables
did not exist, on_define would have been useless.
Historically, large pieces of examples relied on something like
db.define_table('b', Field('c'))
db.b.c.default = 'me'
db.b.c.requires = IS_IN_SET(('me', 'you'))
I guess it was for cleanliness in reading.... I never liked it.
That being said, lots of web2py users started copy/pasting ..... and then
found out that, with lazy_tables enabled, basically this method of coding
meant that you couldn't have "b" lazy because calling db.b.c effectively
istantiate the table (even if you don't use it later in the controllers)
ATM, what I'm using on_define for is only database callbacks.
On Wednesday, July 23, 2014 6:57:18 AM UTC+2, Tim Richardson wrote:
>
> I believe that on_define is always done at table instantiation, so for non
> lazy tables it's done when the request is executed as part of setting up
> the table. so lazy_tables is not mandatory.
>
>
> On Wed, Jul 23, 2014 at 2:37 PM, 黄祥 <steve.van...@gmail.com <javascript:>>
> wrote:
>
>> db = DAL(lazy_tables=True)
>>>
>>>
>> not sure, if lazy_tables = True is mandatory or not, another example for
>> on_define :
>> e.g.
>> def on_define_bank(table):
>> # default
>> table.name.default = ''
>> table.age.default = 30
>> # label
>> table.name.label = T('Name')
>> table.age.label = T('Age')
>> # notnull
>> table.name.notnull = True
>> table.age.notnull = True
>> # required
>> table.name.required = True
>> table.age.required = True
>> # requires
>> table.name.requires = IS_NOT_EMPTY()
>> table.age.requires = IS_INT_IN_RANGE(0, 120)
>>
>> db.define_table('person',
>> Field('name'),
>> Field('age', 'integer'),
>> on_define = on_define_bank)
>>
>> best regards,
>> stifan
>>
>> --
>> Resources:
>> - http://web2py.com
>> - http://web2py.com/book (Documentation)
>> - http://github.com/web2py/web2py (Source code)
>> - https://code.google.com/p/web2py/issues/list (Report Issues)
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>
>
>
> --
>
>
>
> *Tim Richardson, Director*
> GrowthPath, Data-driven profit growth
>
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--
Resources:
- http://web2py.com
- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
- https://code.google.com/p/web2py/issues/list (Report Issues)
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