drupal entity type 和 bundle 概念理解

Entity 在 drupal 里是一个很重要的概念。个人理解：drupal 也是在面向对象的思想上对其提炼，即世上万物皆对象。其概念有点类似生物学上的界门纲目科属种层级关系。Entity type 就是大类，比如水果；Bundle 就是子类，比如西瓜；Field 就是水果属性，比如西瓜是圆的，绿皮带条纹，有籽无籽等。而 Entity 就是更具象指这个西瓜（实例）。

• An entity type is a base class
• A bundle is an extended class
• A field is a class member, property, variable or field instance (depending on your naming preference)
• An entity is an object or instance of a base or extended class

via

In Drupal 8, bundles are a type of container for information that holds the field or setting definitions. They are sometimes called "sub-types". Bundles are optional and in the hierarchy of container types for information they fit below entity types.

• Entity variants (content and configuration; many entities come in pairs, e.g. blocks)
  • Entity types
    • Bundles, or sub-types (optional)

Examples of those container types are as follows:

• Entity Variants:
  1. Content
     • Content Entity Types:
       1. Node
          • Node Bundles, aka Content Types:
            1. Article
            2. Basic page
       2. Taxonomy
          • Taxonomy Bundles, aka Vocabularies:
            1. <Vocabulary A>
            2. <Vocabulary B>
            3. <Vocabulary Etc.>
       3. Blocks
          • Custom Block Bundles, aka Custom Block Types:
            1. <Block Type L>
            2. <Block Type M>
            3. <Block Type Etc.>
       4. User (has no child bundles)
       5. <Custom content entity type X>
       6. <Custom content entity type Y>
       7. <Custom content entity type Etc.>
  2. Configuration
     • Configuration Entity Types:
       1. Custom Block types(has no child bundles?)
       2. View(has no child bundles)
       3. Menu (has no child bundles)
       4. Role (has no child bundles)
       5. <Custom config entity type I>
       6. <Custom config entity type II>
       7. <Custom config entity type Etc.>

via