Re: [Dev-C++] Database program (how do i do that?)

[Devin C. <dcc...@ya...>]

> Hey Listers:
>
> I am trying to learn cpp and I am trying to do a simple application with a
database ( just to hold some notes, comments, etc ).

  I'm learning C++ too, but have the advantage of a good-but-rusty knowledge
of C.  There are some decentish resources on the Web for this; most
importantly, http://www.mindview.com/Books
has two free books on C++.  I've just started vol. 1 and it goes into more
depth than the many online tutorials.

> I have seen around some .dat files, and they seem to be a txt file.  I
know that cpp can create binary file as well.

  '.dat' just means 'data.'  It could be in either format, theoretically.

> Actually, I do not know how to start, then I got a few questions:
>
> 1) Which one is better txt or binary? (In my application all the data is
just text )

  Binaries are usually smaller, since the file doesn't have to hold all the
messy spaces and such.
However, text files have the advantage that they can be loaded into a text
editor like NotePad and examined.  This is helpful while debugging, or if
you want the data file to be human-readable (e.g., a payroll listing.)  If
you -don't- want the data to be easily human-readable (say, for a game that
keeps the data for the villains in a file), then binary is the way to go.

> 2) How do I create a database with txt files or binary files?  Any
suggestions or a good tutorial in the web?

  I haven't played with file I/O streams yet.  There are good tutorials on
the web but it takes some time to find them.  The complete Coronado tutorial
at http://www.swcp.com/~dodrill/controlled/cppdoc/cpptutor.html is my
favourite tutorial; I don't like the format it's stored in, but it's fairly
thorough.  Go through the text and examples carefully.  The Coronado
tutorial's main strength is that it anticipates questions very well - more
than once, I was scratching my head about some detail or another in an
example and the tutorial text said something like 'You may be wondering
about...' or 'Observant students will notice...'  Your mileage will, of
course, vary.
  Another good tutorial is
http://www.zib.de/Visual/people/mueller/Course/Tutorial/tutorial.html.  I
don't like it as much as the Coronado tutorial, because it isn't as
thorough - there's a lot that's skimped over.  But it does talk about what
object-oriented and modular programming are, and explains inheritance, is-a,
has-a, and is-a-kind-of relationships very well.  It's more geared towards
theory than practice.

> 3) Once it was created, how do  I perform a search in database? Do I need
an index table? (I don't even know how to do this)

  That isn't a C++ question; that's a computer science question.  There are
entire courses on this subject.  (I've taken only half of one, but then
again, I read my old computer science texts for fun every now and then.)
  For a first project I'd recommend just making the simplest stupidest
linear searching algorithm possible, something like

function data search( string SearchTarget)
{
    while (!END_OF_DATA_FILE)
    {
        fileread name, data;
        if name = SearchTarget
            return data;
    }
    return SEARCH_FAILED;
}

  If you write your search function 'modularly', then you can replace it
later with something more sophisticated without changing any other part of
the program.  That's one of the main benefits of object-oriented
programming.  If you keep things simple, you'll have a working (if
inefficient) prototype that you can change later.

> I got other questions, but I think I'll start with the basic ones.
>
> I'd appreciate some help with this. I have been studying cpp and I have
passed through all those boring tutorials about language basics. Now I want
to do a real
> application, simple, but real !

  That's the stage I'm at.  I was playing a game a few weeks ago and
thought, 'You know, this game is so algorithmic and object-oriented it'd
make a wonderful first C++ project.'  Right now, I'm a module and a half
from completing my prototype.
>
> Thanks in advance....

  People have helped me, so I feel I ought to return the favour. :)  All I
can give, though, is advice from One Newbie To Another.

--Devin Carless



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