Strapi Content Types

# Strapi Content Builder
            ## Content-types and Fields

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## What is a Headless CMS?
            A content management system that:
            - does not have a front end;
            - generally exposes data via either a REST API or GraphQL;
            - can be used with any frontend, such as vanilla JS, ReactJS, Angular and VueJS.

---
            
            ### Database Terminology
            <dl>
              <dt>Schema (aka: data model)</dt>
              <dd>The “blueprint” of a database which describes how the data may relate to data.</dd>
              <dt>Entity (aka: db table)</dt>
              <dd>A real-world thing or a real-world object.</dd>
              <dt>Attribute (aka: db table column/field)</dt>
              <dd>A definition of a characteristic property of an entity.</dd>
              <dt>Relationship (aka: db join)</dt>
              <dd>A connection between two entities; either one-to-one, one-to-many or many-to-many.</dd>
            </dl>

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## DB terms vs Strapi terms

**Schema** --> **Model**

**Entity** --> **Content-type**

**Attribute** --> **Field**

**Relationship** --> **Relation field**

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## Categories of Strapi Types
            <dl>
              <dt>Collection type</dt>
              <dd>Content-types that can manage several entries.</dd>
              <dt>Single type</dt>
              <dd>Content-types that can only manage one entry.</dd>
              <dt>Components</dt>
              <dd>A re-usable group of types/fields that can be used in multiple collection types and single types.</dd>
            </dl>

---

### Regular (boring) content fields
            Many of the regular types are straight forward:
            - **Text**: Can be short (i.e. titles) or long (i.e. descriptions)
            - **Rich Text**: for long format markdown content
            - **Number**: for quantities, price, etc
            - **Boolean**: for flags and checkboxes
            - **Email**: for uhm, email addresses
            - **Password**: an encrypted field
            - **Enumeration**: for dropdown menus
            - **Media**: For example, images
            - **JSON**: For javascript objects

See: [Strapi Documentation](https://docs.strapi.io/user-docs/latest/content-types-builder/configuring-fields-content-type.html#regular-fields)

---

### Relation fields
            Used for connecting one Content-type to another.

![Illustrations for major relationships](../../assets/images/cms/strapi-relations.png)

See: [Understanding and using Relations in Strapi](https://strapi.io/blog/understanding-and-using-relations-in-strapi)
            
            ---

## One-to-one (rare)
            Content-type A has and belongs to one Content-type B

![Illustration for one-to-one relationships](../../assets/images/cms/one-to-one.png)

**Example**: A person has a unique ID card.

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## One-to-many
            Content-type A belongs to many Content-type B

![Illustration for one-to-one relationships](../../assets/images/cms/one-to-many.png)

**Example**: A country can have many cities but a city can only be in one country.

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## Many-to-many
            Content-type A has and belongs to many Content-type B
            
            ![Illustration for one-to-one relationships](../../assets/images/cms/many-to-many.png)

**Example**: A movie can have many actors and an actor can be in many movies.

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## One way (rare)
            Content-type A has one Content-type B BUT Content-type B is not linked back to A (uni-directional)

Used for performance in large databases.

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## Many way (rare)
            Content-type A has many Content-type B BUT Content-type B is not linked back to B (uni-directional). 
            
            Used for performance in large databases.

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## Components
            Used for grouping commonly used sets of fields that are used in multiple Content-types.
            
            - Components can be _repeatable_ if a Content-type needs more than one of them.

**Example**: a hypertext link is the classic component this groups a link text field with a URL text field. This component can then be used throughout the Content-type Builder.
            
            ---

## Further resources
            - [User Guide](https://docs.strapi.io/user-docs/latest/getting-started/introduction.html)
            - [Developer Documentation](https://docs.strapi.io/developer-docs/latest/getting-started/introduction.html)