A word on validation¶
It’s generally considered a good idea to centralise your data validation in a single place, and a good place to do this is inside your model classes. This is preferable to handling validation alongside form handling code, for example. Placing validation code inside models means that if you extend your application in the future to update your model via an alternative route (say a REST API rather than a form) you can re-use the same validation code.
Despite this, Paris doesn’t provide any built-in support for validation. This is because validation is potentially quite complex, and often very application-specific. Paris is deliberately quite ignorant about your actual data - it simply executes queries, and gives you the responsibility of making sure the data inside your models is valid and correct. Adding a full validation framework to Paris would probably require more code than Paris itself!
However, there are several simple ways that you could add validation to your models without any help from Paris. You could override the save() method, check the data is valid, and return false on failure, or call parent::save() on success. You could create your own subclass of the Model base class and add your own generic validation methods. Or you could write your own external validation framework which you pass model instances to for checking. Choose whichever approach is most suitable for your own requirements.