Note, this is all covered in the online documentation -- I suggest you skim
through the chapter on the DAL:
http://web2py.com/books/default/chapter/29/06/the-database-abstraction-layer
A select returns a Rows object. You must then extract an individual Row
from it, and then the individual field value from the Row. In your case,
you want:
X[0].X
Anthony
On Wednesday, April 29, 2015 at 2:38:05 PM UTC-4, Aydin S wrote:
>
> Thanks Anthony, This works fine, I also added the field name because I
> want to get only the value of X, so I used:
> db(db.Table1).select(db.Table1.X, orderby=~db.Table1.id, limitby=(0, 1))
> However, this does not return the value, I used:
> def index():
> form = SQLFORM(db.Temp).process()
> X = db(db.Table1).select(db.Table1.X, orderby=~db.Table1.id, limitby=(0, 1
> ))
> return (form=form,X=X)
> Then I printed X in the view using {{=X}} which returns:
>
> Table1.X
> 10
>
> As you see this is a column, what I want is the number 10 only. Sorry if
> this is so basic issue.
>
>
>
> On Wednesday, 29 April 2015 10:17:57 UTC-4, Anthony wrote:
>>
>> db.Table1.X is just a field object and doesn't refer to any record in the
>> database. To retrieve a record, you must create a query. In most databases,
>> you can just take the record with the largest ID:
>>
>> db(db.Table1).select(orderby=~db.Table1.id, limitby=(0, 1))
>>
>> That sorts in reverse order based on ID and takes the first record.
>> Alternatively, you could include a record creation timestamp and sort based
>> on that.
>>
>> Anthony
>>
>> On Wednesday, April 29, 2015 at 9:31:50 AM UTC-4, Aydin S wrote:
>>>
>>> Thank you, you are right, right now I have:
>>> def index():
>>> form = SQLFORM(db.X).process()
>>> return dict(form=form)
>>>
>>> and I see the database getting updated with new records.
>>> One last question, I use db.Table1.X to refer to the last entered
>>> record. However, this does not work. How can I make it use the last entered
>>> row?
>>>
>>> On Wednesday, 29 April 2015 08:27:22 UTC-4, Anthony wrote:
>>>>
>>>> See answer on SO: http://stackoverflow.com/a/29932995/440323
>>>>
>>>> On Tuesday, April 28, 2015 at 9:35:31 PM UTC-4, Aydin S wrote:
>>>>>
>>>>> It looks like the scheduler which is a model file does not see
>>>>> variable X in the database!
>>>>>
>>>>> On Tuesday, 28 April 2015 21:19:14 UTC-4, Aydin S wrote:
>>>>>>
>>>>>> No, the value of the form gets processed every time the scheduler
>>>>>> runs.
>>>>>>
>>>>>> On Tuesday, 28 April 2015 21:07:42 UTC-4, Dave S wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Tuesday, April 28, 2015 at 6:01:04 PM UTC-7, Aydin S wrote:
>>>>>>>>
>>>>>>>> This is probably very simple, sorry in advance!
>>>>>>>> I have a form defined in a model file:
>>>>>>>> db.define_table('table1',
>>>>>>>> Field('X', 'integer'))
>>>>>>>> I have a controller that is also defined as:
>>>>>>>> def index():
>>>>>>>> form = SQLFORM(db.X)
>>>>>>>> return dict(form=form)
>>>>>>>>
>>>>>>>>
>>>>>>> In my index view file I have:
>>>>>>>>
>>>>>>>> <h2>Input form</h2>
>>>>>>>> {{=form}}
>>>>>>>>
>>>>>>>> I want to use value X in a scheduler defined as a model like:
>>>>>>>>
>>>>>>>> A = X+2
>>>>>>>>
>>>>>>>> The form shows up as expected. I enter a value in it and submit it.
>>>>>>>> The scheduler is running as expected. However it looks like the value
>>>>>>>> X
>>>>>>>> never gets set to what I enter.
>>>>>>>> Any idea?
>>>>>>>>
>>>>>>>>
>>>>>>> Do you process the form once the user has entered the input?
>>>>>>>
>>>>>>> /dps
>>>>>>>
>>>>>>>
>>>>>>
--
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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