Data Format Brainstorm

Data Format Brainstorm

[Stephen Cacclin]

Hello all,

I am looking for some helpful input from the various comp.* communities. 

Basically I want to know how various databases, languages, protocols etc.
store different data types. In other words, how are signed/unsigned integers,
floating point numbers, date types, booleans etc. written to disk?  

Any database, language, machine type, protocol or other method is welcome! 
Please feel free to share your most obscure references... 

*** Please respond with email since I am polling a number of groups. 

If I receive enough input, I will post a complete overview. 
Thanks in advance.

Stephen Cacclin

Re: Data Format Brainstorm

[Salman Halim]

In article <cacclin.789345537@vanbc>,
Stephen Cacclin <cacclin@vanbc.wimsey.com> wrote:
>Hello all,
>
>I am looking for some helpful input from the various comp.* communities. 
>
>Basically I want to know how various databases, languages, protocols etc.
>store different data types. In other words, how are signed/unsigned integers,
>floating point numbers, date types, booleans etc. written to disk?  
>
>Any database, language, machine type, protocol or other method is welcome! 
>Please feel free to share your most obscure references... 
>
>*** Please respond with email since I am polling a number of groups. 
*blind ignorance to this*

>
>If I receive enough input, I will post a complete overview. 
>Thanks in advance.
>
>Stephen Cacclin

hmm..  i don't really know how databases do their stuff, but i can't think of
an example where i was able to issue a command to pascal which was the
equivalent of:  store this array of boolean to disk in file bool.dat.  how it's
stored is up to the programmer.  some store it as text file (simple ascii on
pc), others perform compression for large data, especially numeric or string.

the SOURCE file on most pc compilers is stored simply as an ascii file (which
means you could edit it just about any bloody where you so choose and then
compile it using the language compiler).

what DOES differ on occasion is how data types are stored in MEMORY (eg.
integers take two bytes, longints take four, a byte obviously takes one etc.
etc.) -- fun fun fun. . .

hope i've completely babbled on uselessly and made no sense at all,

salman.

Re: Data Format Brainstorm

[Mariusz Zydyk]

Stephen Cacclin (cacclin@vanbc.wimsey.com) wrote:
: Hello all,

: I am looking for some helpful input from the various comp.* communities. 

: Basically I want to know how various databases, languages, protocols etc.
: store different data types. In other words, how are signed/unsigned integers,
: floating point numbers, date types, booleans etc. written to disk?  

: Any database, language, machine type, protocol or other method is welcome! 
: Please feel free to share your most obscure references... 

: *** Please respond with email since I am polling a number of groups. 

------- Since you set the follow-ups to all those newsgroups, a folloup
to your post will be automatically routed to them. Enough of that though...

-------- The way you store anything to disk is up to you, th eprogrammer.
You can usually write non-integer numbers to disk same way they are stored
in memory to conserve space. You might expand them into readable form and
save it with all the decimals which will take up 16 or so bytes. Booleans
are stored any way you want. Write them as strings 'True' & 'False', numbers
0 & -1 or any two numbers, or since you can have only 2 states, compress
8 into one byte, '00000001' would be 7 False and 1 True. Of course it is
easier to use tools provided with the compiler to store data, but even there
you can have lots of ways of doing this.
Most database programs will store the data in some peculiar fashion, and
also encrypted [most likely that is]. To find out their formats look at
some sites [don't know which ones though] for the file format info.

                      --==[> zydyk@cpsc.ucalgary.ca <]==--

Re: Data Format Brainstorm

[Robert Dewar]

did you really have to cross-post your reply to all those groups? The  guy
asked for email to prevent this. It is clearly not the kind of question whose
answer is of interest to all these groups.

I find it annoying when people to this kind of blanket post to find 
info when they are too lazy to do a bit of preliminary research first
to find references, but the followups compound the irritiation. Especially
when you read several of the groups involved.