Re: Designing DB in accordance with the relational model

On Nov 11, 11:29 pm, Kentauros <joker..._at_gmail.com> wrote:
> In a given game, characters have list of characteristics. Some of
> those characteristics are mandatory, every character in the game has
> them. Some of them are optional. Between the games, these lists of
> characteristics changes. Some characteristics disappear, some new
> appear. Mandatoriness/optionality may change.
I think I'd rephrase.

In a given game there is a list of mandatory characteristics. There is a list of optional characteristics. Each character in the game has every characteristic from the mandatory list, can have any number of characteristics from the optional list, and has no characteristics not mentioned in those lists.

Hm, I got an idea, but I'd like Erwin to examine it (he invented handling missing info with S by C, so...).

I make a relvar with predicate "In game <Game> characteristic <Characteristic> is <Mandatory> and has domain which example value is <Type>", where <Game>'s domain is, um, games, restricted with list of existing games (possibly a FK to Games relvar), <Characteristic>'s domain is CHAR, <Mandatory> is BOOLEAN and <Type>'s domain is alpha. Received on Thu Nov 11 2010 - 21:40:40 CET