#Overview

This step of our Getting Started tutorial covers Reference type fields.

References are relations between two or more content entries that exist in your project. With references, you can reuse content entries by connecting them to one another. For instance, in our project, a product content entry could be both a standalone product that a potential customer can browse, but also a reference linked to a different product content entry, as part of a related products section.

References

References have a type, direction, and cardinality that define the relationship:

• The type allows us to select if one or more models can be referenced and lets us select which models those will be.
• The direction allows choosing between one-way references, which allow querying content only from one side, or two-way references, which add a reverse-field to query content from both sides.
• The cardinality allows defining whether it will be possible to connect one or many entries to the parent entry, as well as the directions of that relation.

The way you configure a reference will result in one of four possibilities:

• One-to-one reference: It allows adding a reference to one content entry from one model configured as referenceable. For example, you could use this to link a blog post to an author. One-to-one reference
• One-to-many reference: It allows adding references to multiple content entries from one model configured as referenceable. For example, you could use this to link a blog post to its multiple authors. One-to-many reference
• Many-to-many reference: It allows adding references to multiple content entries from the different models configured as referenceable. For example, you could use this to link your products to the categories they belong to. In this case, a product can have multiple categories, and category can have multiple products. Many-to-many reference
• Many-to-one reference: It allows adding references to multiple content entries of the parent model to one model configured as referenceable. For example, you could use this to link an author to all their related blog posts. Many-to-one reference

We'll learn how to configure some of them in the context of our e-commerce project, so we can later use them in the content editor.

To be able to establish relations in the content, we first need to configure the relations in our schema. Our project will use different types of references to connect models in different ways, but we won't be covering all possibilities in this tutorial. You can learn about all of them here.

#Products and categories

In a previous step, we created models for Product & Product category. We want to be able to select categories our product belongs in every time we create a listing. We will create a reference that will make it possible for customers to browse categories besides looking for specific items.

To link these two models, let's click on the Product model to open it and select the Reference field from the right sidebar. You'll find it under Relation.

Since this is a many-to-many reference type, we'll first define the relationship, then configure the reference, and finally the reverse field.

We'll use the following information:

Finally, click Add to save.

We'll see that it's been added at the bottom. Let's use the six-dots handlebar to move it upwards, under the slug field.

Now that we've added the product category reference, we'll be able to work on the content editor later on to both create our categories and reference those categories in our product listings.

#Landing page sections

We want our Landing page model to provide featured content through blog posts, allow users to browse our product categories, and also have a section where our business information can be displayed. We'll do this through relations.

#Blog Post

First, we are going to connect our Blog Post model. In the Landing page model in the Schema builder, we'll add the Reference field from the right sidebar.

We'll use the following information:

Finally, click Add to save.

#Product category

Now, we are going to connect our Product category model. Let's add a Reference field from the right sidebar again.

We'll use the following information:

Finally, click Add to save.

#Seller information

Last, we're going to connect our Seller information model. Let's see if you can add a reference by yourself now.

This reference needs to have almost the same characteristics as the last two we added. We'll use the following information:

Finally, click Add to save.

Your Landing page model should look like this:

Your Landing page model so far