[Lazarus] Embedded database for Lazarus/Linux

[Hans-Peter Diettrich]

Jürgen Hestermann schrieb:

> Forgive me my naivity (I never used a database yet)

I'm also not a DB power user, but...

> but just as an example: If you want to read a complete directory branch 
> (with thousands of files and directories) every 5 minutes in a loop and 
> want to store this information together with other information (like 
> date/time
> of first appearance) at the end of each loop so that it's available even 
> after a reboot, would you use a database for this?
> If yes, how would the tree structure be defined in the database?

Depends ;-)

In your example...

> I just did this using a simple binary file and it was quite easy to do 
> and it's speed is amazing. If my data changes, I simply delete the file 
> and start from cratch.

... I'd not bother with storing the results at all. Databases become 
extremely important when you can *not* simply rebuild your data from 
scratch.


> If I see the delays that applictions like Thunderbird
> produce when simply moving an email to another folder (the hard disk 
> spins for a minute or so) then I am happy that I never was forced to use 
> a database.

That's because TB does *not* use a database, at least not standard DB 
that is designed for fast transaction processing. Instead TB holds all 
information in one file per folder, so that moving a piece from one 
folder to another one means to rewrite two such (huge) datafiles.


You see how important the right use of the right storage model is in 
practice?

DoDi