14.1. Code Generation Based on the Model

In a web application, data access operations can be categorized as one of the following:

• Creation of a record
• Retrieval of records
• Update of a record (and modification of its columns)
• Deletion of a record

These operations are so common that they have a dedicated acronym: CRUD. Many pages can be reduced to one of them. For instance, in a forum application, the list of latest posts is a retrieve operation, and the reply to a post corresponds to a create operation.

The basic actions and templates that implement the CRUD operations for a given table are repeatedly created in web applications. In symfony, the model layer contains enough information to allow generating the CRUD operations code, so as to speed up the early part of the back-end interfaces.

14.1.1. Example Data Model

Throughout this chapter, the listings will demonstrate the capabilities of the symfony admin generator based on a simple example, which will remind you of Chapter 8. This is the well-known example of the weblog application, containing two Article and Comment classes. Listing 14-1 shows its schema, illustrated in Figure 14-1.

Listing 14-1 - schema.yml of the Example Weblog Application

propel:
  blog_article:
    id:          ~
    title:       varchar(255)
    content:     longvarchar
    created_at:  ~
  blog_comment:
    id:          ~
    article_id:  ~
    author:      varchar(255)
    content:     longvarchar
    created_at:  ~

Figure 14.1 Example data model

There is no particular rule to follow during the schema creation to allow code generation. Symfony will use the schema as is and interpret its attributes to generate an administration.