7个基本的Drupal面试问题 *

The five layers, starting from the bottom layer, are as follows:

1. Data (nodes, etc.). 在任何东西可以在网站上显示之前，它必须作为数据输入.
2. Modules. Modules are functional plugins that are either part of the Drupal core or are contributed modules that build on Drupal’s core functionality.
3. Blocks and menus. Blocks can be used to present anything, 所以Drupal站点上的任何内容(除了主要内容), breadcrumbs, (主/次菜单)通常是一个块. Blocks are an extensible core feature of Drupal with a simple API provided by the block module. 块类似于内容管理系统中的“小部件”，但是是高度一般化的. Menus 链接(菜单项)的集合是用来浏览网站的吗. The Menu module provides an interface to control and customize the menu system that comes with Drupal. By default, 新的菜单项被放置在一个名为Navigation的内置菜单中, 但是管理员也可以创建自定义菜单.
4. User permissions. User permissions are defined for various roles and users are assigned to these roles in order to grant them the defined permissions.
5. Themes and templates. drupal体系结构的顶层概念层是主题. 这主要由XHTML和CSS组成, with some PHP variables intermixed, 这样drupal生成的内容就可以放在合适的位置. Also included with each theme is a set of functions that can be used to override standard functions in the modules in order to provide complete control over how the modules generate their markup at output time. 主题可以包含一个或多个模板, 取决于网站的复杂性和它的设计方式.

Drupal comes with a built in taxonomy system that allows for categorization of the nodes on a site.

分类法系统允许对术语进行任意定义, 以及将这些术语任意组织成词汇表. 可以创建的词汇表的数量没有限制, 词汇表中可以包含的术语数量也没有任何限制.

词汇表也可以有自由标记，这意味着, 而不是提前输入具体条款, users may enter tags freely at the time the content is created and those tags automatically become terms in that vocabulary.

Drupal的分类法系统是其最强大、最灵活的特性之一.

The Field API allows custom data fields to be attached to Drupal entities and takes care of storing, loading, editing, and rendering field data. Any entity type (node, user, etc.) can use the Field API to make itself “fieldable” and thus allow fields to be attached to it. Other modules can provide a user interface for managing custom fields via a web browser as well as a wide and flexible variety of data type, form element, and display format capabilities.

The Field API defines two primary data structures, Field and Instance, and the concept of a Bundle. 字段定义了可以附加到实体的特定类型的数据. 字段实例是附加到单个Bundle的字段. A Bundle is a set of fields that are treated as a group by the Field Attach API and is related to a single fieldable entity type.

For example, suppose a site administrator wants Article nodes to have a subtitle and photo. 使用字段API或字段UI模块, the administrator creates a field named ‘subtitle’ of type ‘text’ and a field named ‘photo’ of type ‘image’. The administrator (again, via a UI) creates two Field Instances, one attaching the field ‘subtitle’ to the ‘node’ bundle ‘article’ and one attaching the field ‘photo’ to the ‘node’ bundle ‘article’. 当节点系统使用Field Attach API来加载Article节点的所有字段时, it passes the node’s entity type (which is ‘node’) and content type (which is ‘article’) as the node’s bundle. field_attach_load() then loads the ‘subtitle’ and ‘photo’ fields because they are both attached to the ‘node’ bundle ‘article’.

字段定义表示为键/值对数组.

注意，以上答案摘自 Drupal API Documentation, where more information can be found.

Drupal网站上的所有内容都作为“节点”存储和处理。. A node is any piece of individual content (e.g.、网页、文章、论坛主题、博客条目等.). Note, though, that omments are not stored as nodes but are always connected to a node.

The ability to create different “content types” is a way Drupal allows you to have different kinds of nodes for different purposes. For example, an “article” is one content type, a “book page” is another, and a “blog entry” yet another. 您还可以创建自己的新内容类型.

Treating all content as nodes provides a great deal of flexibility that facilitates and simplifies creating new types of content. It also makes it easy to apply new features or changes to all content of a particular type.

Using the Views module, 您可以从站点的数据库中获取内容，并将其作为列表呈现给用户, posts, galleries, tables, maps, graphs, menu items, blocks, reports, forum posts etc. 可以显示不同的内容类型，包括节点、用户和其他包.

Views UI, a submodule within Views, provides a graphical interface underneath which lies a powerful SQL query builder that can access virtually any information in your database and display it in any format.

Different displays can present the query results as pages with fixed URLs on your site (or URLs accepting arguments), blocks, feeds, or panel panes.

您还可以使用视图来显示相关内容或实现上下文过滤器. For example, you can display a list of users along with links to the content they have created and/or you can display customized content to a user according to their user ID.

More information is available in the Views documentation on the Drupal site.

Rails是Ruby的通用web应用程序框架. 它旨在帮助程序员在构建各种类型的网站时更有效率, not just CMSs. And note that it’s for “programmers”. 除非您打算编写服务器端代码, 你不能指望仅仅使用Rails就能完成很多事情(但是如果你真的打算写代码的话), Ruby和Rails都是非常高效的).

Drupal是一个内容管理系统，有数百个这样的系统. It happens to be written in PHP, but it’s modular design and large collection of available modules and themes make it possible to design and implement a large variety of web sites without writing a line of code. 但最重要的是，它本质上是一个CMS. 您的站点的需求离CMS的最佳点越远, Drupal成为您最佳选择的可能性就越小.

Drupal’s hook system is essentially a mechanism for implementing custom features without needing to make any modifications to the Drupal core. There are specific places where the Drupal core can invoke custom functions defined in modules to enhance the functionality of core. 这些地方被称为“钩子”，并且具有定义良好的接口.

Hooks make it possible, for example, for a module to define new URLs and pages within a site (hook_menu), to add content to pages (hook_block, hook_footer, etc.), set up custom database tables (hook_schema), and so on.

假设您想要更改核心“Contact”表单. To do so, you can implement hook_form_alter in your custom module and provide any cuistom functionality that you’d like in that function. Drupal will check all form_alter hooks in all modules, so your hook will be picked up and your custom code will be applied to the “Contact Form”.

So overall, Drupal hooks are just functions defined per the Drupal standards that allow you to extend Drupal and alter or extend core functionality without modificing any core code.