Database Design: Storing Map Locations

Question

When working on a game, I developed a database that used X/Y coordinates, roughly as:

CREATE TABLE Map
(
    MapId INT IDENTITY PRIMARY KEY,
    X INT NOT NULL,
    Y INT NOT NULL,
    North INT FOREIGN KEY REFERENCES Map(MapId),
    South INT FOREIGN KEY REFERENCES Map(MapId),
    East INT FOREIGN KEY REFERENCES Map(MapId),
    West INT FOREIGN KEY REFERENCES Map(MapId)
);

(I'm not at my editor, so that may have syntax errors.)

I then implemented the path searching algorithm (A*, specifically) inside a stored procedure.

1. Is there a better way to implement this coordinates system?

2. I had implemented it in SQL Server, since that is what I had on hand and what I was familiar with. Is there anything in another database system that would've simplified this problem?

It may make a difference to know that this, being a game, is strictly a grid system. That may simplify (or complicate) the problem.

Edit:

Some sample data:

map_id      x           y           north       east        south       west
----------- ----------- ----------- ----------- ----------- ----------- -----------
20          502         501         26          33          21          18
21          502         502         20          22          87          19
22          503         502         33          23          88          21

Answer 1

If the game area is strictly static, then my preference would be to use the coordinates as the primary key.

On postgres, I'd probably do that using a composite type. I don't think there is a direct equivalent in SQL Server - hopefully someone will correct me if I'm wrong.

Whether this will simplify the problem or not depends on how exactly you have implemented your searching algorithm - can you post more details on that?