Re: [libreoffice-users] database or spreadsheet

On 02/07/2012 05:17 PM, e-letter wrote:
> On 07/02/2012, Nino Novak<nn.libo@kflog.org>  wrote:
> > As a consequence: It would help most, if the database set up barrier could
> > be
> > lowered.
> >
> > We therefore should ask (and try to learn) what makes database creation so
> > difficult, and how could we contribute to ease the learing curve?
> >
> > Or directly: how can we make database creation easy and a low-threshold
> > task?
> The statement made by someone that databases requires planned design
> _first_ is important to remember. But for a novice how do you make the
> plan?
For example you wish to develop an inventory of all your books. You look 
at the data you have for each book such as title, author, subject, 
publisher, etc. and determine what data is needed. Next look at each 
group of data for a book. A book can have multiple authors and multiple 
subjects but only one title, publisher, ISBN number. This suggests that 
there should be three tables in the initial: title, author, and subject.

First design you have a main table of based on the title each book - 
primary key titleid, an author table with each author linked by a 
"foreign key" to the correct title id, and a subject table with each 
subject linked by a "foreign key" to the correct titileid. The author 
and subject tables have their own internal ids. I like to have an 
integer id for each row as the primary key. You can use any column or 
group of columns as a primary key as long as each generates a unique 
value. Using integer id fields makes implementing foreign keys easier.

To refine the design, you want every individual piece of data only 
inputted once and you may find it advisable to split say the title table 
into two tables,; one for titles and one for publishers.

Also, determine the best type for each data column, text, date, time, 
integer, floating point number, etc and determine which data must be 
entered, which has a default value you can override, and which can have 
no data entered. The database engine will enforce these rules when one 
enters the data. If any is the wrong type or required it will through an 
error.
> This is why the original poster was asked the question why did
> spreadsheet names have to be changed, although he doesn't think it
> important. It is important to know the objective. For example, we
> could be asked how to manoeuvre a 10-tonne truck a distance of 50
> metres, when if we knew the objective was to buy a drink from the shop
> across the road, we could advise it would be easier to walk! A silly
> analogy but hopefully understood.
>
> Maybe the way to promote the option of designing databases is to
> describe particular scenarios and show how particular tasks can be
> performed using either a database or a spreadsheet. Users would then
> see two tutorial scenarios to show the (dis)advantages.
>
> Hopefully someone can suggest such a scenario or two please?


--
Jay Lozier
jslozier@gmail.com


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