Doctrine_manual-1-2-en

Chapter 15: Inheritance 232
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15-5
class Group extends Entity
{ }
Here is the same example in YAML format. You can read more about YAML in the YAML
Schema Files (page 195) chapter:
---
# schema.yml
# ...
Entity:
columns:
name: string(30)
username: string(20)
password: string(16)
created_at: timestamp
updated_at: timestamp
User:
inheritance:
extends: Entity
type: simple
Group:
inheritance:
extends: Entity
type: simple
Lets check the SQL that is generated by the above models:
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15-6
// test.php
// ...
$sql = Doctrine_Core::generateSqlFromArray(array('Entity', 'User',
'Group'));
echo $sql[0];
The above code would output the following SQL query:
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15-7
CREATE TABLE entity (id BIGINT AUTO_INCREMENT,
username VARCHAR(20),
password VARCHAR(16),
created_at DATETIME,
updated_at DATETIME,
name VARCHAR(30),
PRIMARY KEY(id)) ENGINE = INNODB
When using YAML schema files you are able to define columns in the child classes but
when the YAML is parsed the columns are moved to the parent for you automatically. This
is only a convenience to you so that you can organize your columns easier.
Concrete
Concrete inheritance creates separate tables for child classes. However in concrete
inheritance each class generates a table which contains all columns (including inherited
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