Use MySQL Workbench, throw a screenshot of your schema as an ERD on
the #mysql channel on freenode.
They'll give you what you're looking for, i.e.: a rational schema.
On Tue, Oct 2, 2012 at 10:08 AM, Cliff Kachinske <cjk...@gmail.com> wrote:
> Read up on indexing tables. Properly indexed tables can retrieve data much
> more quickly because they cut down the number of rows the dbms has to
> examine.
>
> This is especially true across joins. MySQL does not index foreign keys so
> joined queries can take a looooooooong time.
>
>
> On Monday, October 1, 2012 9:27:42 AM UTC-4, curiouslearn wrote:
>>
>> Thanks Alec. I don't think I will reach those numbers, ever, for one game.
>>
>> This has nothing to do with web2py, but I have a MySQL database with
>> about a 700,000 records and selects are quite slow in it. Some simple
>> queries take 7-8 seconds per query, which is slow in the context of a
>> game. Probably I have not set it up well. But that is what caused me
>> to worry about this.
>>
>> Anyhow, thanks for the advice.
>>
>>
>> On Mon, Oct 1, 2012 at 9:13 AM, Alec Taylor <alec.t...@gmail.com> wrote:
>> > Those are really low numbers.
>> >
>> > When you are getting closer to a billion games a week you should
>> > consider a schema change, e.g.: multi-tenant.
>> >
>> > On Mon, Oct 1, 2012 at 10:54 PM, Curiouslearn <curiou...@gmail.com>
>> > wrote:
>> >> Hi Alec,
>> >>
>> >> I am using mysql backend. I will most probably host it on dotcloud,
>> >> using their Python and MySQL service.
>> >>
>> >> I think as suggested by Cliff and you, I will create only one set of
>> >> tables for all games. As of now I will probably have only about 50
>> >> datapoints per team. There are no images. Right now I don't anticipate
>> >> more that 20 games per 2-3 months; hence about 20000 (20 teams per
>> >> game x 50 datapoints X 20 games) data points per 2-3 months. I was
>> >> thinking of what would happen when more people use it. But I suppose
>> >> I should not worry about that now.
>> >>
>> >> Thanks.
>> >>
>> >>
>> >> On Mon, Oct 1, 2012 at 7:48 AM, Alec Taylor <alec.t...@gmail.com>
>> >> wrote:
>> >>> Probably not. Where are you hosting this?
>> >>>
>> >>> E.g.: Google App Engine doesn't have "tables", so the whole concept is
>> >>> "irrelevant" there.
>> >>>
>> >>> Also, how much data are you talking per team, and how many teams do
>> >>> you expect to be in the database?
>> >>>
>> >>> Unless you're storing an inordinate amount of images or realtime VOIP
>> >>> recording you won't need to worry about efficiency.
>> >>>
>> >>> On Mon, Oct 1, 2012 at 9:21 PM, Curiouslearn <curiou...@gmail.com>
>> >>> wrote:
>> >>>> Hi Cliff,
>> >>>>
>> >>>> Thanks very much for your input. I am new to databases and appreciate
>> >>>> the advice.
>> >>>>
>> >>>> I was also thinking of the alternative you are talking about. But
>> >>>> thought that as the number of games played increased, this would
>> >>>> increase the number of records in the tables and make database access
>> >>>> slow. Is this not a good reason to create different set of tables for
>> >>>> each game? Would appreciate any advice regarding this.
>> >>>>
>> >>>> Thanks.
>> >>>>
>> >>>> On Mon, Oct 1, 2012 at 4:46 AM, Cliff Kachinske <cjk...@gmail.com>
>> >>>> wrote:
>> >>>>> Do not let your tables proliferate this way.
>> >>>>>
>> >>>>> You need a teams table, even if it contains only the team name or
>> >>>>> some other
>> >>>>> identifier.
>> >>>>>
>> >>>>> You need a games table.
>> >>>>>
>> >>>>> You need to relate these two. One game has multiple teams, I
>> >>>>> suppose, so
>> >>>>> that makes a one-to-many relationship.
>> >>>>>
>> >>>>> If the same team can participate in more than one game, you need a
>> >>>>> many to
>> >>>>> many relationship.
>> >>>>>
>> >>>>> The DAL chapter in the Web2py manual explains how to implement
>> >>>>> these.
>> >>>>>
>> >>>>> Next you add a game_id field to both your offers and decisions
>> >>>>> tables. That
>> >>>>> ties these events to the game. Alternatively you could simply call
>> >>>>> the
>> >>>>> field 'game', assuming you can remember that it contains the record
>> >>>>> id of
>> >>>>> the game in question.
>> >>>>>
>> >>>>> You also need to add a team_id field to these tables. That ties
>> >>>>> each record
>> >>>>> to the team involved.
>> >>>>>
>> >>>>> This data structure will allow you to select records for each game,
>> >>>>> for each
>> >>>>> team in a game. If the teams persist, you can also select all the
>> >>>>> records
>> >>>>> related to the team.
>> >>>>>
>> >>>>> On Sunday, September 30, 2012 5:31:50 PM UTC-4, curiouslearn wrote:
>> >>>>>>
>> >>>>>> Hello,
>> >>>>>>
>> >>>>>> This is a question about recommended practice for doing the
>> >>>>>> following:
>> >>>>>>
>> >>>>>> I want to create a web interface for creating a setup for new
>> >>>>>> games. For
>> >>>>>> example, the web interface will let me specify
>> >>>>>> name of the game, number of teams etc. Based on this information I
>> >>>>>> want to
>> >>>>>> create new database tables for the game.
>> >>>>>> Should the table definitions be given in a controller function,
>> >>>>>> such as in
>> >>>>>> the example below? Is that the recommended way
>> >>>>>> to do this, or is there another way that you would recommend.
>> >>>>>>
>> >>>>>> Thank you.
>> >>>>>>
>> >>>>>> **Controller function for creating tables**
>> >>>>>>
>> >>>>>> def createtables():
>> >>>>>> if request.post_vars:
>> >>>>>> experimentname = request.post_vars.experimentname
>> >>>>>> numteams = int(float(request.post_vars.numteams))
>> >>>>>> teams_tablename = "{0}_teams".format(experimentname)
>> >>>>>> offers_tablename = "{0}_offers".format(experimentname)
>> >>>>>> ardecisions_tablename =
>> >>>>>> "{0}_ardecisions".format(experimentname)
>> >>>>>> migrate_teamstablename =
>> >>>>>> "{0}.table".format(teams_tablename)
>> >>>>>> migrate_offerstablename =
>> >>>>>> "{0}.table".format(offers_tablename)
>> >>>>>> migrate_ardecisionstablename =
>> >>>>>> "{0}.table".format(ardecisions_tablename)
>> >>>>>> db.define_table(teams_tablename,
>> >>>>>> Field('teamname', 'string', length=40,
>> >>>>>> required=True,
>> >>>>>> unique=True, notnull=True),
>> >>>>>> Field('passwd', 'password'),
>> >>>>>> Field('role', 'string', length=20, required=True,
>> >>>>>> default='NA'),
>> >>>>>> format = '%(teamname)s',
>> >>>>>> migrate=migrate_teamstablename)
>> >>>>>> # Table showing the ask amount of the first mover
>> >>>>>> referencestring = 'reference {0}'.format(teams_tablename)
>> >>>>>> db.define_table(offers_tablename,
>> >>>>>> Field('round', 'integer'),
>> >>>>>> Field('askamount', 'integer'),
>> >>>>>> Field('payoff', 'integer'),
>> >>>>>> Field('teamname_id', referencestring),
>> >>>>>> migrate = migrate_offerstablename)
>> >>>>>>
>> >>>>>>
>> >>>>>> # Table accept-reject decisions
>> >>>>>> db.define_table(ardecisions_tablename,
>> >>>>>> Field('round', 'integer'),
>> >>>>>> Field('acceptorreject', 'string',
>> >>>>>> length=2),
>> >>>>>> Field('payoff', 'integer'),
>> >>>>>> Field('teamname_id', referencestring),
>> >>>>>> Field('offerer_id', referencestring),
>> >>>>>> migrate = migrate_ardecisionstablename)
>> >>>>>>
>> >>>>>>
>> >>>>>> teamnames = maketeamnames(numteams)
>> >>>>>> for tname in teamnames:
>> >>>>>> db[teams_tablename].update_or_insert(teamname=tname)
>> >>>>>> db.experimentlist.insert(experimentname=experimentname)
>> >>>>>> return dict()
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>> --
>> >>>>>
>> >>>>>
>> >>>>>
>> >>>>
>> >>>> --
>> >>>>
>> >>>>
>> >>>>
>> >>>
>> >>> --
>> >>>
>> >>>
>> >>>
>> >>
>> >> --
>> >>
>> >>
>> >>
>> >
>> > --
>> >
>> >
>> >
>
> --
>
>
>
--
