Drupal concepts

The big picture

Of code and (wo)mens

Drupal is based on a core (opens in a new tab) that provides the kernel and its own modules and themes. The core is maintained by a dedicated crew. It provides a starting point that can be extended by other projects maintained by the community, contributed projects: modules, themes, or distributions.

Drupal site building concepts

Full documentation is available on the Drupal User Guide (opens in a new tab).
Here is a summary of the concepts for site builders.

Storage and entity types

Storage (persistence) is the responsibility of entities that can be

Content entity : stored on the database, used by any Drupal user.
Configuration entity : stored on configuration files, mostly used by the developer and the site builder.

Content type and node

[/admin/structure/types] and [/admin/content]

A node is the basic piece of content
Nodes can be from several types (known as “content types”), describing the business model: Article, Basic Page are coming out of the box, Event, Session, Training, Organization, … are customized.
Nodes can be created, edited and translated with the contributor role.

Taxonomy vocabulary and term

[/admin/structure/taxonomy]

Taxonomy vocabularies are used for content (node, user, ...) categorization
Each vocabulary is composed of terms
Terms can have an hierarchy and multiple parents

User and roles

[/admin/people] and [/admin/people/roles]

Users are can access the Drupal backend, if they have the permission to do so
Users are grouped by roles
Roles can be cumulated
Each role has a set of permissions

Blocks

[/admin/structure/block]

Blocks are used to handle page display exceptions
They can appear on regions, defined by themes
Their display can be based on conditions (by path inclusion or exclusion, by role, …)

Field

Fields can specialize content types, taxonomy vocabularies, users and blocks.
Fields can be shared among the same entity type (you can share the field Image with Basic Page and Article), allows one single instance on the same content type (you cannot create two image fields with the same machine name on the same content type, but you can create a field_image and a field_logo).
Fields are not shared among different entity types, so they can adopt the same machine name: you can create a field_image for vocabularies, even if it already exists for content types.
Some are simple / scalar (text, long text, float) while other can be composite (address)
Fields have cardinality (one to many values)
Fields can be used to reference any another entity (the Article content type can reference a Article Type vocabulary).
Fields can be defined as sub structure with some modules (e.g. Field Collection or Paragraphs) that can also have cardinality. Note that Field Collection is probably on its way to be deprecated.
Fields can be synced among content translation or be defined as translatable

Views

[/admin/structure/views]

Views are SQL query builders that are primarily focusing on one entity type.
They can use filters that are implicit or exposed to the user, relationships and much more...

Translation

Translation occurs at several levels

Content entity translation
Configuration entity translation
User interface translation : system global, like button labels or pagination

More information about translation

A note about naming conventions

Historically, depending on the context (user interface, code, ...) we can find several synonyms for Drupal data structures.

Content types

Content type can have several "bundles" (example: Page, Article) that are producing nodes.

We should talk about Entity type of Node for a Content type and Node type for a bundle.
This is the case in the code.

Vocabularies

Taxonomy can have several vocabularies that are producing Taxonomy terms.
We should talk about Entity type of Term and Term type.

Display and view modes

Entities can have several Display modes (Teaser, ...). In some situations they are called View modes.
Do not get confused with the Views that are SQL query builders.

Title and name

Node entities have title while Taxonomy Term have name. In the code, you usually can refer to it as label.

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