I am creating a new theme for use on two or three sites.
My code needs to be able to exclude/include posts with specific Categories which can simply be done if you know the Cat-id.
Of course, Categories are numbered at set-up time and as I believe I cannot set a Category to a particular Cat-id I have decided to set global constants in one place and set a group of names to the corresponding Cat-id and use the constant throughout the theme code.
At present I am doing this with define() in index.php at the wordpress root to be sure that the constants are available throughout the theme but I would rather set them inside my theme and out of danger of WordPress updates!
a) am I right about Category-ids
b) is there some place where my define() will be executed every time?