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Newsgroups: comp.lang.python
Date: Sun, 27 Nov 2011 00:49:14 -0800 (PST)
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Subject: Re: my new project, is this the right way?
From: 88888 Dihedral <dihedral88888@googlemail.com>
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On Sunday, November 27, 2011 4:29:52 PM UTC+8, 88888 Dihedral wrote:
> On Sunday, November 27, 2011 12:03:26 PM UTC+8, Matt Joiner wrote:
> > Sounds like you want a key-value store. If it's a lot of data, you may
> > still want a "database", I think it's just relational databases that
> > you're trying to avoid?
> >=20
> > On Sun, Nov 27, 2011 at 10:41 AM, 88888 Dihedral
> > <dihe...@googlemail.com> wrote:
> > > On Saturday, November 26, 2011 1:01:34 AM UTC+8, rusi wrote:
> > >> On Nov 14, 3:41=A0pm, Tracubik <aff...@b.com> wrote:
> > >> > Hi all,
> > >> > i'm developing a new program.
> > >> > Mission: learn a bit of database management
> > >> > Idea: create a simple, 1 window program that show me a db of movie=
s i've
> > >> > seen with few (<10) fields (actors, name, year etc)
> > >> > technologies i'll use: python + gtk
> > >> > db: that's the question
> > >> >
> > >> > since i'm mostly a new-bye for as regard databases, my idea is to =
use
> > >> > sqlite at the beginning.
> > >> >
> > >> > Is that ok? any other db to start with? (pls don't say mysql or si=
milar,
> > >> > they are too complex and i'll use this in a second step)
> > >> >
> > >> > is there any general tutorial of how to start developing a databas=
e? i
> > >> > mean a general guide to databases you can suggest to me?
> > >> > Thank you all
> > >> >
> > >> > MedeoTL
> > >> >
> > >> > P.s. since i have a ods sheet files (libreoffice calc), is there a=
 way to
> > >> > easily convert it in a sqlite db? (maybe via csv)
> > >>
> > >> To learn DBMS you need to learn sql
> > >> [Note sql is necessary but not sufficient for learning DBMS]
> > >> I recommend lightweight approaches to start with -- others have
> > >> mentioned access, libreoffice-base.
> > >> One more lightweight playpen is firefox plugin sqlite-manager
> > >>
> > >> > Is that ok? any other db to start with? (pls don't say mysql or si=
milar,
> > >> > they are too complex and i'll use this in a second step)
> > >>
> > >> Correct. First you must figure out how to structure data -- jargon i=
s
> > >> normalization.
> > >> After that you can look at transactions, ACID, distribution and all
> > >> the other good stuff.
> > >
> > > If I have a fast hash library =A0that each hash function supports ins=
ertion and deletion and can be frozen to be stored into the file system if =
desired and retrieved lator . Can I use several hashes to replace a databas=
e that is slow and expensive?
> > >
> > > --
> > > http://mail.python.org/mailman/listinfo/python-list
> > >
>=20
> A database with most entries in fixed bytes and types and several  types =
that can have varied lengths of 8 to 256 bytes. If an entry is larger than =
256 bytes, it will be saved as a file but only the file name is saved in my=
 data base.
>  =20
> Each entry is just a type and value stored  in a row of my database.
> I''ll limit the number of entries in a row or so called a recored to some=
 limit first, 1024 first.=20
>   =20
> Can I do this in 1024 hashes in python ?
Sorry I 'll use (k=3Dcolumn_in_a_row, v=3Dvalue) and (k=3Dvalue, v=3Dcolumn=
_in_a_row)
Thus, two hashes per column in  my database, therefore  2048 hashes to mana=
ge the data base. I'll reserve 24 entries per row for book keeping.=20
Thus the record can have 1000 entries maximum first.=20
The number of record can be very large.=20
Each value will be a string with type 1 byte  and the stored value 8 to 255=
 bytes represented as a string when fetching the value can be auto-transfor=
med=20
according to the type.  The sort and search will be rewritten for the compa=
rison operator.=20