what is it called when one record stores many values like "2,3,4,5,10" ?

[bradsears]

hi

Vbulletin stores a user's 2ndary usergroup in a comma delimited list in one record of the user recordset
- example = "1,6,2,4,5,22"
- all I need to do (via my external script) is be able to:
- check if a certain number is in there
- add a number if it is not
- remove a number if I need to (user leaves the group)

I'm a struggling asp->php convert and I don't want to have to re-invent the wheel on this one so I am wondering:
- is there a special name for a record that contains a comma delimited list like this
- are there special sql query terms that support this
- is processing of lists like this perhaps a built-in php function

Thanks