Let's consider you as a customer doing some online shopping in my fancy online shop. There are some things I (the online merchant) need to know about you. Namely, who you are and what you want to buy.
As a best practice, I should organize the things I want to know about you into related chunks. For example, you are my Customer and you placed an Order. Those are my types of data.
Now, what, specifically, do I want to know about you as my Customer. For sure your First Name, Last Name, Shipping Address, Billing Address, Contact Information, and whatever else. I also want to capture specifically what item you ordered, how many you want, and how much I am going to charge you. Each of those bits of data is a field.
When you are using my fancy web site, I need to present to you a form to fill out; your view of the data I am collecting about you.
Data type: the name of the container that holds related bits of data (Customer, Order, Billing Address, etc).
Data field: the names of the specific bits of data collected in the data type
User view: the web form (page) used to present the data fields to the user
In the order in which you would put these things together:
Data model: an abstract, visual representation of elements of data and how they relate to each other. Could be drawn on a white board, a napkin, a PPT slide, etc.
Data type: the implementation of the data model in Pega. Usually organized into containers that hold related elements of data (Customer, Order, Billing Address, etc). Could be in any application, thanks for using Pega :)
Data field: the names of the specific bits of data (elements) collected in the data type. For example, a Customer data type might have the fields First Name, Last Name, Email address, Phone number, Billing address (which is most likely a data type of its own), etc.
Data object: This is so not a term in Pega, but hey - who am I. This term is borrowed (and misused) from OO programming concepts where data + behavior = object. In general, when you see this term used in the context of Pega, it refers to an instance of a data type. For example, we have that Customer data type. Blake is one of my customers, but so is Betty, and Biff, and Irshad, etc. Each of you is a data object.
Data page(s): A visual, human readable representation of all application data stored in cache in Pega.
User view: the web form (page) used to present the data fields to the use.
Give me a few days and I will put together a visual.