Defining the Entities

In this chapter you will learn

• how to configure your entities to map them to the database.
• how to define relationships.

Important: Be sure, that your database tables correspond to your entities. Mind that datatypes are correct. Set indices and foreign keys. PPA will not do that for you.

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Basic

Classes

You can annotate a class with @table(name = '<tablename>'). So the class will be mapped to the database table <tablename>. If the parameter name is not defined, than the class will be mapped to its short name. Don't forget, that the resulting tablename is always assumed to be lowercase.

Note: It is not necessary to define the @table annotation anyway. The only requirement, a class must fullfill, is to extend the class \PPA\core\Entity.

Example:

/** @table(name = "user") */
class User extends \PPA\core\Entity { }

Properties

You can annotate class properties with a few annotations. To map a class property to a column it is necessary to make the @column annotation. PPA will not interfere in any other way to your class definitions. It does not even matter what scope your properties have.

Example:

/** @column(name = "username") */
private $username;

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Relations

Relations are the powerful feature of PPA. PPA can automatically resolve all sort of relations you want to define. Fetched rows will be converted automatically to real objects. Below is described how you can annotate the class-properties appropriate.

OneToOne

OneToOne-Relations occur, when one parent record or field has either zero or one child record only. Respectively, when one Entity has a property which value is represented by null or another Entity.

This case is can be represented by annotations as follows:

/**
 * @Column(name="role_id");
 * @oneToOne(fetch="eager", mappedBy = "_PPA_examples_entity_Role")
 */
private $role;

• Firstly, you need to tell PPA which column is represented by the Entity, by the @column annotation. This column will mostly have a foreign key and refer to a primary value of another table.
• Secondly, you must define the relation type and declare the fetch-type and the class to be mapped. Look here for info.

OneToMany

/**
 * @oneToMany(fetch = "lazy", mappedBy = "_PPA_examples_entity_OrderPosition")
 * @joinTable(x_column = "order_id")
 */
protected $orderPos;

ManyToMany

/**
 * @manyToMany(fetch = "lazy", mappedBy = "_PPA_examples_entity_Right")
 * @joinTable(name = "role2right", column = "role_id", x_column = "right_id")
 */
private $rights = array();