2010/11/12 Mirek Zvolský :
> That's not the case of
> http://zvolsky.alwaysdata.net/crm2.jpg
DISCLAIMER: I'm not experienced with large-scale database designs.
Now that I've gotten that out of the way...
What's the meaning of 'created_by' in this set-up? If it's meant to be
taken as 'record crea
2010/11/12 Mirek Zvolský :
>>> Mariano Reingart
>
> Thanks for your response and practical experience with large system.
>
> I think the problem is clear:
> In current web2py philosophy the same data model becames valid or
> invalid based on the order of table definition commands. And if a
> model
> Is there a reason for not sticking the record creation inside of its own
> table?
Hi Tadeus,
This is just an example. I have used it to show Massimo and others,
that the simplest part of CRM application model, if you change
"created_by" from type "string" to type "reference..", then there is
no
Right. I get it now.
Is there a reason for not sticking the record creation inside of its own
table?
--
Thadeus
2010/11/12 Mirek Zvolský
> hich person is an employee of which company,
> 2) which person has created the company record,
> 3) which person has created the person records,
> all 3
>> Mariano Reingart
Thanks for your response and practical experience with large system.
I think the problem is clear:
In current web2py philosophy the same data model becames valid or
invalid based on the order of table definition commands. And if a
model is complex, then there is no possibility
>> Thadeus Burgess
>> WRong. cr2 is a really really bad design.
>> Database 101, any many to many relationship must be defined through a link
>> table.
I'm sorry, but you missunderstand the term "many to many relationship"
and the term "relation" at all.
Because, of course, "one relation" means e
2010/11/11 Mirek Zvolský :
> Oh no!,no!,no! please no!
> I still hope it's my mistake only. I simple cannot believe, that this
> is behaviour of web2py data model. Are we in year 1960?
> Friends, take a look to the oldest database implementations older as
> SQL language, in MS-DOS times, f.e. dBase
True.
On Nov 11, 1:23 pm, Thadeus Burgess wrote:
> I still do not agree.
>
> If you run into this issue you can always offset the created_by fields...
>
> db.define_table('audit_table',
>
> Field('tablename'), Field('record_id', 'integer'),
>
> Field('created_by', db.auth_user),
>
> )
>
> If you
I still do not agree.
If you run into this issue you can always offset the created_by fields...
db.define_table('audit_table',
Field('tablename'), Field('record_id', 'integer'),
Field('created_by', db.auth_user),
)
If you ever did need to audit, just look it up in this table. Then you don't
h
I agree with you that using a link table is better. This was my
original argument.
Yet often the need to sign tables (created_by) will suddenly cause a
duplication of tables because lots of link tables have to be added and
queries changed. This is what I meant by good case.
Massimo
On Nov 11, 12
WRong. cr2 is a really really bad design.
Database 101, any many to many relationship must be defined through a link
table.
Redesign CR2 like so...
db.define_table('person', created_by('person'))
db.define_table('company',...created_by('company'))
db.define_table('person_company', id_perso
Ok. Your crm2jpg makes a good case. You proved me wrong.
I will try add this by the week-end.
Massimo
On Nov 11, 11:24 am, Mirek Zvolský wrote:
> -> mdipierro
> I have prepared 2 pictures, and in this time there is new post from
> you about company/author. Interesting that my pictures are about
-> mdipierro
I have prepared 2 pictures, and in this time there is new post from
you about company/author. Interesting that my pictures are about the
same :-)
Model of your CRM application application is here:
http://zvolsky.alwaysdata.net/crm1.jpg
Such model can be implemented in web2py, but orde
Wasn't this a no-no?.
I got wrist slapped once for suggesting it. :)
On Nov 11, 11:53 am, mdipierro wrote:
> BTW. This is possible:
>
> db.define_table('company',
> Field('name'),
> Field('created_by', 'integer'))
> db.define_table('person',
> Field('last_name'),
> Field('compan
BTW. This is possible:
db.define_table('company',
Field('name'),
Field('created_by', 'integer'))
db.define_table('person',
Field('last_name'),
Field('company_id', 'reference company'))
db.company.created_by.requires=IS_IN_DB(db,'person.id','%
(last_name)s')
although my object sta
I was thinking of scripted table creation and keeping things simple
but I understand what you are saying (or reiterating since it has been
said before).
If no valid case is made then I could change the manual to explain why
it is not supported.
Pros/Cons?
Denes.
On Nov 11, 11:18 am, mdipierro
>From a syntactical point of view it would not take much to support
multi-table circular references in web2py. That is not why they are
not implemented, They are not implemented because they are bad design
practice.
If this is a 1-1 relation, there is no need to table A to refer to B
and B to A. I
Yes its the point.
When you simply switch the definition order to person table first,
web2py will raise the same error with company table doesnt exist yet.
David
On 11 lis, 17:05, DenesL wrote:
> Some of you have missed Mirek's point, and he has a very valid one.
> The problem is circular refere
Some of you have missed Mirek's point, and he has a very valid one.
The problem is circular references.
There are ways around it but no elegant solution yet.
There was discussion some time ago about lazy evaluation of tables.
I also would like to see this solved in web2py.
Denes.
On Nov 11, 1
Your error seems to be coming from the fact you do not have defined a person
model. Since web2py is a functional designed you must define person table
before you can reference it.
I use the following self-referential table and have never had a problem.
db.define_table('participant',
#... lots of
>> Here's a link to the section in the book:
>> http://www.web2py.com/book/default/chapter/06#Self-Reference-and-Aliases
Yes, I know this, and from that reason I always use 'reference..'
style syntax.
However this is about very special foreign keys, which targets to same
table (to the primary key
Oh no!,no!,no! please no!
I still hope it's my mistake only. I simple cannot believe, that this
is behaviour of web2py data model. Are we in year 1960?
Friends, take a look to the oldest database implementations older as
SQL language, in MS-DOS times, f.e. dBase III, FoxBase, Clipper. And
earlier o
Here's a link to the section in the book:
http://www.web2py.com/book/default/chapter/06#Self-Reference-and-Aliases
On Nov 11, 8:44 am, Mirek Zvolský wrote:
> I have simplest model:
>
> db.define_table('company',
> Field('name'),
> Field('created_by', 'reference person'))
> db.define_tabl
Cross reference between tables, see this post
http://groups.google.com/group/web2py/browse_thread/thread/b3cb1ce223649e0f/14688d53b3d88857?lnk=gst&q=table+cross+reference#14688d53b3d88857
On Nov 11, 12:44 am, Mirek Zvolský wrote:
> I have simplest model:
>
> db.define_table('company',
> Fie
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