Is it bad practice to have a lot of static functions? I am using Yii framework and I realized I have a lot of static functions in my model classes. I put all my functions that have to do with Users into the UsersModel (I do the same for other models too) but I end up with a lot of static functions. Just wondering how you guys deal with this. A lot of these functions are just query builder functions instead of lazy loading because I need to increase database performance.
Example functions:
User::getUserFromCampaign(1)
User::getUsersNotInCamapaigns()
User::isAdmin()