Can't be blank validation is the first option you want to enable for most form fields. It allows you to be sure that user will input data to your form, instead of submitting blank form
Validation types: can't be blank (required field), validate only on submit. The best way to see how it works – real example.
Login to QuintaDB online database
Create new project using templates
Go to the Form builder menu
Ok, so now we have a form with fields. Good. Let's have a talk about validation. Open the field editing page by clicking left mouse button on the field or using context menu:
Open the Validation tab and mark "Can't be blank" and "Validate only on submit" options
Can't be blank - this option does not allow a user to leave fields blank.
Validate only on submit - if you select this system feature it will check all the fields only after you press “Create” button.
Also, you can make Required field from the Form builder menu: