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Data Structure Definition

In the previous chapter, the CRUDServiceProvider got the path to a crud.yml told. This is where CRUDlex gets it's information about what tables with what fields exists in your database. We will build up a valid, small example as we continue in this chapter.

The first items in the crud.yml are the entities. Each entity is describing a single table with it's fields. Let's say we have two tables, libraries and books. So we define two entities with the same name. Note that this name is your choice, the table name of the database gets defined in a second.

library:
book:

In this case, the entities would be available under this URLs (assuming you mounted the CRUDController under "/crud"):

http://.../crud/library

http://.../crud/book

Now we declare the labels and the tables. The label is used for displaying links in the navigation and in some messages:

library:
    label: Library
    table: library
book:
    label: Book
    table: book

So far, so good. In our minimal example, a library has a name and a Book has an author, a title and the amount of pages as fields.

library:
    label: Library
    table: library
    fields:
        name:
            type: text
            label: Name
book:
    label: Book
    table: book
    fields:
        author:
            type: text
            label: Author
        title:
            type: text
            label: Title
        pages:
            type: int
            label: Title

Note that the yml keys "name", "author" and "title" directly name the database column names. Each one has a type and a label here. The type defines the database type and the label is used in various places to display the field. In this example, only simple string types are used and an integer for the book pages.

Beside this fields, the CRUDlex MySQL implementation assumes that you have some more fields per table:

  • id int(11) NOT NULL AUTO_INCREMENT: the id of each row
  • created_at datetime NOT NULL: a timestamp when the row was created
  • updated_at datetime NOT NULL: a timestamp when the row was the last time updated
  • deleted_at datetime DEFAULT NULL: defines when this entry was deleted. CRUDlex uses a soft delete mechanism hiding all rows where this is not null
  • version int(11) NOT NULL: (will be) used for optimistic locking

See the CRUDlexSample.sql in the sample project for the exact table creation.

As a last addition, we only want to show the author and title in the big list view of the books. We can do it by using the listFields entry:

library:
    label: Library
    table: library
    fields:
        name:
            type: text
            label: Name
book:
    label: Book
    table: book
    listFields: [id, created_at, updated_at, author, title]
    fields:
        author:
            type: text
            label: Author
        title:
            type: text
            label: Title
        pages:
            type: int
            label: Title

It is a simple list referencing the fields. Note the usage of the internal fields "id", "created_at" and "update_at". "version" is not yet used and every row where "deleted_at" is not null is marked as deleted, so this field would make no sense to display.

Only strings and integers are boring, so in the next chapter, all possible data types are presented.

Previous: Setup

Next: Data Types

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