*bump* anything?
On Wed, Sep 4, 2019 at 5:02 PM Michael P. McDonnell <[email protected]>
wrote:
> So I must be missing something, but here's what I have right now:
>
> tournament_table = Table(
> 'tournament',
> Base.metadata,
> Column('id', UUID(as_uuid=True), primary_key=True))
>
> team_table = Table(
> 'team',
> Base.metadata,
> Column('id', UUID(as_uuid=True), primary_key=True,
> * Column('tournament_id', UUID(as_uuid=True), ForeignKey('tournament.id
> <http://tournament.id>'), nullable=False),*
> Column('display_name', String(length=255), nullable=False),
> UniqueConstraint('tournament_id', 'display_name'))
>
> team_person_table = Table(
> 'team_person',
> Base.metadata,
> *Column('team_id', UUID(as_uuid=True), ForeignKey('team.id
> <http://team.id>'), primary_key=True*),
> *Column('person_id', UUID(as_uuid=True), ForeignKey('person.id
> <http://person.id>'), primary_key=True)*)
>
> person_table = Table(
> 'person',
> Base.metadata,
> Column('id', UUID(as_uuid=True), primary_key=True))
>
>
> In my current model I can create
>
> Tournament A, Team A (paired to Tournament A), Team B (also paired to
> Tournament A), and Team C (also paired to Tournament A)
> I can then assign *Person Z* to Team A, Team B and Team C separately
> without throwing an integrity exception.
>
> How can I make it so that doesn't happen?
>
>
> On Wed, Sep 4, 2019 at 4:53 PM Derek Lambert <[email protected]>
> wrote:
>
>> If I'm understanding correctly...
>>
>> You're on the right track. I'd use a composite primary key on
>> |team_person|, consisting of foreign keys from |person| and |team|, and
>> another composite key (or unique index) on the |team| to |tournament|
>> table. This lets the database do all the work.
>>
>> -Derek
>>
>> On Wednesday, September 4, 2019 at 4:16:02 PM UTC-5, Michael P. McDonnell
>> wrote:
>>>
>>> Hey -
>>> I'm again at a loss of what to google, and as this will ultimately need
>>> to be represented in some fashion in sqlalchemy, I figured this is a great
>>> place to start:
>>>
>>> I have a |person| table and a |team| table with a many to many table in
>>> between |team_person|.
>>> Simple enough!
>>>
>>> Now - to make it fun.
>>> |team| has a relationship to |tournament|
>>> How can I prevent a user from joining more than 1 team in a given
>>> tournament?
>>>
>>> I thought about adding a 3rd column to my M2M table,
>>> (team_tournament_person), but that could still fail because it could be a
>>> team from tournament x, tournament y's ID and a Person Q's ID.
>>>
>>> So any suggestions on what I should be googling, and then how to
>>> implement in SA would be hugely appreciated!
>>>
>>> Thanks!
>>>
>> --
>> SQLAlchemy -
>> The Python SQL Toolkit and Object Relational Mapper
>>
>> http://www.sqlalchemy.org/
>>
>> To post example code, please provide an MCVE: Minimal, Complete, and
>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
>> description.
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>>
>
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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