Models

All models in Rack applications extend from the abstract Model class, defined in include/models/Model.class.php. This class provides a basic implementation for CRUD (create, read, update, and delete) functionality for a single database table. It utalizes the PDO prepared statements to construct queries to help preventing SQL injections.

A Model object should never be manually created, as Rack provide a function get_model($name) in include/init.php that creates an instance of a Model object for you when need it. The following snippet demonstrates its use:

<PHP> $model = get_model('Registration'); $registrations = $model→get(); </PHP>

Basic queries can be executed using the functions get, create, update and delete or their by_id counterparts. The create and update functions accept a list with 'fieldname'=>'value' pairs that should be used to modify the database.

The get, update and delete functions also accept an array with filter conditions. These conditions will be appended to the query and multiple conditions will be joined with AND. In this array, filter conditions should be specified as 'fieldname__function' => $value.

Supported comparison functions are:

• eq: Tests if the field value is equal to (=) another value.
• ne: Tests if the field value is not equal to (<>) another value.
• lt: Tests if the field value is less than (<) another value.
• lte: Tests if the field value is less than or equal to (⇐) another value.
• gt: Tests if the field value is greater than (>) another value.
• gte: Tests if the field value is greater than or equal to (>=) another value.
• in: Tests if the field value is in a list.
• contains: Tests if the field contains a string value (LIKE '%value%' ). Note that % and _ will not be automatically escaped.
• isnull: Tests if the field value is NULL (if 'field__isnull'=>true) or not NULL (if 'field__isnull'=>false).

If the comparison function is omitted ('field' => $value), the default of eq is used.

The get function also supports custom ordering by passing a list of field names. Descending ordering can be achieved by adding a minus in front of the field name. The following example will order first by study and then by birthdate in descending ordering: ['study', '-birthdate'].

• __construct($db, $table=null): The variable $db is a PDO object. This value will be set by get_model. $table is the name of the table as it's stored in the database.
• protected query($query, array $input_parameters=[]) Expects a query and input parameters that that can be used for PDO prepared statements.
• protected query_first($query, array $input_parameters=[]) Same as query, but returns only the first result.
• get(array $conditions=[], array $order=[], $get_first=false)
• get_by_id($id, $field='id')
• create(array $values) Returns inserted ID.
• update(array $data, array $conditions=[]) Use with caution!
• update_by_id($id, array $data, $field='id')
• delete(array $conditions) Use with caution!
• delete_by_id($id, $field='id')