Hey there,

the user chooses 0 to n entries in a specified order and i've to save said order of the entries in the user table. My approach of saving the order in a single string (1,5,3,2) worked, but I think that's not exactly considered best practice.

Table User: (int ID; string username; string order) e.g: "1";"Hans";"1,2,3,4"
Table Entries: (int ID; string content) e.g. "1";"Fruityloops"

Any ideas how to improve this?

depends entirely on what you want to do with it

i.e. database design means squat without knowing the SQL that will be run against it

To be specific: The user customize the menu of a webpage, he can arrange the order of the menu items and close any of them. In order to print the menu for the current user, i need to get the order (Select Order From User Where Username = $logged_in), after that i select the actual context of every displayed Item (Select * From Entities where ID=$id).

looks like you're okay with running two queries, then ... which is good

be careful naming the string in the users table, because ORDER is a reserved word

the second query will use IN instead of equals, but you will still ahve to sequence them properly

if you're using mysql, you can use the handy-dandy FIELD function in your ORDER BY clause

Why not a 3rd table?

user_entry: user_id*, entry_id*, entry_sequence

Then to select the entries, just do a join between entry and user_entry ordering by entry_sequence.

If you want to be really strict, you can put a separate unique constraint on (user_id, entry_sequence), though this can make updating the sequence a bit of a nuisance.

consider storing the ORDER BY clause as a variable against the users current login.

eg
futurity logontime transaction ID ORDER BY manufacturer, type, price DESC