Re: Suggestion needed on data storage format in text file

Manish wrote:
The project I am developing doesn't involves database. I want to parse
the mailbox file (.mbx) and store the summary in the text file for fast
retrieval and display of information in the Inbox page.

The sugegsted format are as:

#1

ID [4 bytes]: Subject [100 bytes]: To Address[100 bytes]: From
Address[100 bytes]...etc...

#2

Instead of preassining fixed size to variable (as actual data may be
much less or can grew to more), we can store the values continuously,
seperated by some unique seperator (#|#, *#*, ...)

1324#|#Hi, How are you#|#me@xxxxxxxxxx#|#you@xxxxxxxxxx#|# ... and so
on


Which of these will be the efficeint one (as there will be frequent
insert/delete/update of the individual information, eg. set message as
read ..., delete message ..., new message ...)

Also please suggest on how to determine the variable size (100 bytes as
in #1), and assign the size to the variable accordingly and read it
(differentiate multiple variables) when required.

Thanks.

Manish


Personally, I'd use a database. I wouldn't even try a flat file for this. Too much work trying to keep things straight.

But you asked about the formats. The fixed length fields will have extra space any time the amount of data is less than that of the amount reserved. Then you run into the problem of someone who gets very verbose with their subject line and exceeds the 100 characters. And 4 bytes allows up to 9999 ID's. Is that enough? Or are you going to try to read/write binary (not easy in PHP)?

The second one is problematical because the user may include your separator in its Subject: line (or even name/address if you pick the wrong character).

Two other ways - use CSV format, which is well documented and supported by PHP and other programs. Or, add a length field at the beginning of each field, specifying how many characters in the following field.

But I'd still use a database.


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Jerry Stuckle
JDS Computer Training Corp.
jstucklex@xxxxxxxxxxxxx
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