How it is made?

[zmref]

How does each character/player in a server saved their game? I mean like saved inventory, char stats, map location, job class, level, etc.

where can I found this in database without opening their own accounts?

[starkBastard]

main.sql

[Mystery]

Using the main.sql found here: https://rathena.svn.sourceforge.net/svnroot/rathena/trunk/sql-files/main.sql has all the tables needed for characters to be saved. They are saved automatically by the server itself:

// Database autosave time
// All characters are saved on this time in seconds (example:
// autosave of 60 secs with 60 characters online -> one char is saved every
// second)
autosave_time: 300

// Min database save intervals (in ms)
// Prevent saving characters faster than at this rate (prevents char-server
// save-load getting too high as character-count increases)
minsave_time: 100

// Apart from the autosave_time, players will also get saved when involved
// in the following (add as needed):
// 1: after every successful trade
// 2: after every vending transaction
// 4: after closing storage/guild storage.
// 8: After hatching/returning to egg a pet.
// 16: After successfully sending a mail with attachment
// 32: After successfully submitting an item for auction
// 64: After successfully get/delete/complete a quest
// NOTE: These settings decrease the chance of dupes/lost items when there's a
// server crash at the expense of increasing the map/char server lag. If your
// server rarely crashes, but experiences interserver lag, you may want to set
// these off.
save_settings: 127

https://rathena.svn....map_athena.conf

You would need to be setup as a SQL server since we no longer support Text based servers (if you're using eAthena it's a different story then).