If you are talking about levels as super nerd suggest then what you do is create a part of your DB program which constructs the level from data.
When you call this code - whether it's a procedure or a function - you simply supply the data for the current level.
For a very simple example, you could have a single procedure which creates a matrix. All you do is set up the parameters before you do the Gosub. Eg:
MWid=2000: MHig=2000: MTileX=50: MTileZ=50
Gosub MakeLevel
MakeLevel:
If Matrix Exist(1) Then Delete Matrix 1
Make Matrix 1,MWid,MHig,MTileX,MTileZ
Return
You can call the same procedure many times to create the correct size matrix for any level by just changing the variables before using the gosub.
Obviously, you would use a lot more data for setting up a proper level in a game, such as matrix heights, textures, object positions and so on, but the principles are the same.
You can even have all of your level data in separate files on the hard disk and call the MakeLevel procedure with the name of the level data file. The procedure then simply opens up the file on disk and uses the data in it to build the level.
TDK_Man