When creating your models, there are a number of special variables you can set in order to gain access to Cake functionality:

$primaryKey

If this model relates to a database table, and the table's primary key is not named 'id', use this variable to tell Cake the name of the primary key.

$recursive

This sets the number of levels you wish Cake to fetch associated model data in find() and findAll() operations.

Imagine you have Groups which have many Users which in turn have many Articles.

$transactional

Tells Cake whether or not to enable transactions for this model (i.e. begin/commit/rollback). Set to a boolean value. Only available for supporting databases.

$useTable

If the database table you wish to use isn't the plural form of the model name (and you don't wish to change the table name), set this variable to the name of the table you'd like this model to use.

$validate

An array used to validate the data passed to this model. See Chapter "Data Validation".

$useDbConfig

Remember the database settings you can configure in /app/config/database.php? Use this variable to switch between them - just use the name of the database connection variable you've created in your database configuration file. The default is, you guessed it, 'default'.