Home arrow PHP arrow Page 4 - Adding Ordering and Grouping Clauses to the CodeIgniter Library with Method Chaining

The custom model class's full source code - PHP

Welcome to the tenth installment of a series on method chaining in PHP 5. Comprised of twelve tutorials, this series teaches you the key concepts that surround the implementation of chainable methods within PHP classes, and shows how to put them to work to create a custom library for the popular CodeIgniter framework.

TABLE OF CONTENTS:
  1. Adding Ordering and Grouping Clauses to the CodeIgniter Library with Method Chaining
  2. Creating the JOIN, ORDER BY and GROUP parts of a query
  3. Conditional queries: adding WHERE modifiers to a SELECt statement
  4. The custom model class's full source code
By: Alejandro Gervasio
Rating: starstarstarstarstar / 1
November 25, 2009

print this article
SEARCH DEV SHED

TOOLS YOU CAN USE

advertisement

As I stated in the prior segment, itís time to see how the set of chainable methods defined earlier fits in into the structure of the abstract model class. How can this be done? Simply by showing its full source code, which has been included below. Take a look at it:

The MIT License

 

Copyright (c) 2008 Simon Stenhouse

 

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

 

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

 

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 

class AbstractModel

{

protected $table = '';

protected $fields = array();

protected $validation = array();

protected $error_prefix = '<p>';

protected static $instance = NULL;

protected $ci = NULL;

protected $db = NULL;

 

// Factory method that creates a singleton model object

public static function factory($model)

{

if (self::$instance == NULL)

{

$model = ucfirst($model);

self::$instance = new $model;

}

return self::$instance;

}

 

// Constructor

public function __construct()

{

$this->ci = & get_instance();

$this->db = $this->ci->db;

$table = strtolower(get_class($this)) . 's';

if ($this->db->table_exists($table))

{

$this->table = $table;

$this->fields = $this->db->field_names($this->table);

}

else

{

return;

}

}

 

// Sets a new property for the model

function __set($property, $value)

{

if(in_array($property, array_merge($this->fields, array('error', 'result')), TRUE))

{

$this->$property = $value;

}

}

 

// Gets the value of an existing property of the model

function __get($property)

{

if(isset($this->$property))

{

return $this->$property;

}

return NULL;

}

 

// Fetches rows from specified table

public function fetch($limit = NULL, $offset = NULL)

{

$data = array();

foreach ($this->fields as $field)

{

if (isset($this->$field) AND $this->$field != '')

{

$data[$field] = $this->$field;

}

}

$query = !empty($data) ? $this->db->get_where($this->table, $data, $limit, $offset) : $this->db->get($this->table, $limit, $offset);

if ($query->num_rows() > 0)

{

$this->result = $query->result();

return $this;

}

$this->error = 'No rows were returned.';

return FALSE;

}

 

// Inserts a new row into the specified database table

public function save()

{

$data = array();

foreach ($this->fields as $field)

{

if (isset($this->$field))

{

$data[$field] = $this->$field;

 

}

}

// if there is any data available go ahead and save/update row

if( !empty($data))

{

// validate input data

if ($this->validate($data) === FALSE)

{

$this->error = $this->get_error_string();

return FALSE;

}

// if id property has been set in the controller update existing row

if ( !empty($this->id))

{

// Update existing record

$this->db->where('id', $this->id);

$this->db->update($this->table, $data);

}

else

{

// otherwise insert new row

$this->db->insert($this->table, $data);

$this->id = $this->db->insert_id();

}

return TRUE;

}

$this->error = 'No valid data was provided to save row.';

return FALSE;

}

 

// Deletes a row

public function delete()

{

if (isset($this->id))

{

$this->db->where('id', $this->id);

$this->db->delete($this->table);

return TRUE;

}

$this->error = 'Error deleting row.';

return FALSE;

}

 

// Builds SELECT part of the query

public function select($select = '*', $protect_identifiers = TRUE)

{

if ($select != '*' AND !empty($select))

{

$select = explode(',', $select);

foreach ($select as $key => $field)

{

if ( !in_array($field, $this->fields, TRUE))

{

unset($select[$key]);

}

}

$select = !empty($select) ? $select : '*';

}

$this->db->select($select, $protect_identifiers);

return $this;

}

 

// Builds the select MAX part of the query

public function select_max($field, $alias = '')

{

if (in_array($field, $this->fields, TRUE))

{

$this->db->select_max($field, $alias);

}

return $this;

}

 

// Builds the select MIN part of the query

public function select_min($field, $alias = '')

{

if (in_array($field, $this->fields, TRUE))

{

$this->db->select_min($field, $alias);

}

return $this;

}

 

// Builds the select AVG part of the query

public function select_average($field, $alias = '')

{

if (in_array($field, $this->fields, TRUE))

{

$this->db->select_min($field, $alias);

}

return $this;

}

 

// Builds the select SUM part of the query

public function select_sum($field, $alias = '')

{

if (in_array($field, $this->fields, TRUE))

{

$this->db->select_min($field, $alias);

}

return $this;

}

 

// Builds the JOIN part of the query

public function join($table, $join, $join_type = '')

{

if ( !empty($table) AND !empty($join))

{

$this->db->join($table, $join, $join_type);

}

return $this;

}

 

// Builds the ORDER BY part of the query

public function order_by($field = 'id', $order = 'ASC')

{

if (in_array($field, $this->fields, TRUE))

{

$this->db->order_by($field, $order);

}

return $this;

}

 

// Builds the GROUP BY part of the query

public function group_by($field)

{

if (in_array($field, $this->fields, TRUE))

{

$this->db->group_by($field);

}

return $this;

}

 

// Builds the LIKE part of the query using the AND operator

public function like($field, $match, $position = '')

{

if (in_array($field, $this->fields, TRUE) AND !empty($match))

{

$this->db->like($field, $match, $position);

}

return $this;

}

 

// Builds the OR LIKE part if the query using the OR operator

public function or_like($field, $match, $position = '')

{

if (in_array($field, $this->fields, TRUE) AND !empty($match))

{

$this->db->or_like($field, $match, $position);

}

return $this;

}

 

// Builds the NOT LIKE part of the query

public function not_like($field, $match, $position = '')

{

if (in_array($field, $this->fields, TRUE) AND !empty($match))

{

$this->db->not_like($field, $match, $position);

}

return $this;

}

 

// Builds the DISTINCT part of the query

public function distinct()

{

$this->db->distinct();

return $this;

}

 

// Builds the WHERE part of the query using AND and other operators

public function get_where($where, $protect_identifiers = TRUE)

{

if ((is_string($where) OR is_array($where)) AND !empty($where))

{

$this->db->where($where, $protect_identifiers);

}

return $this;

}

 

// Builds the OR WHERE part of the query using OR and other operators

public function get_or_where($where, $protect_identifiers = TRUE)

{

if ((is_string($where) OR is_array($where)) AND !empty($where))

{

$this->db->or_where($where, $protect_identifiers);

}

return $this;

}

 

// Builds the WHERE IN part of the query

public function where_in($field, $values)

{

if (in_array($field, $this->fields, TRUE) AND is_array($values) AND !empty($values))

{

$this->db->where_in($field, $values);

}

return $this;

}

 

// Builds the WHERE NOT IN part of the query

public function where_not_in($field, $values)

{

if (in_array($field, $this->fields, TRUE) AND is_array($values) AND !empty($values))

{

$this->db->where_not_in($field, $values);

}

return $this;

}

 

// Builds the OR WHERE NOT IN part of the query using the OR operator

public function or_where_not_in($field, $values)

{

if (in_array($field, $this->fields, TRUE) AND is_array($values) AND !empty($values))

{

$this->db->or_where_not_in($field, $values);

}

return $this;

}

}

There you have it. I donít want to exaggerate, but the custom model class is definitely starting to look much more functional, mostly because of the incorporation of the chainable methods that you saw earlier in this article.

Feel free to introduce your own changes and improvements into this CodeIgniter model class, so you can arm yourself with a more solid grounding in using method chaining with PHP 5.

Final thoughts

Over this tenth chapter of the series, I demonstrated how useful the method chaining approach can be for expanding the functionality of the previous custom CodeIgniter model class. As you saw for yourself, adding a few common modifiers to a query is reduced to coding some modular chainable methods and nothing else.

In the penultimate tutorial, Iím going to finish developing the abstract model class by adding to it some extra methods, which will perform such additional tasks as validating incoming data, building error strings, and much more.

You know what my final suggestion is, but here we go again: donít miss the next part!



 
 
>>> More PHP Articles          >>> More By Alejandro Gervasio
 

blog comments powered by Disqus
escort Bursa Bursa escort Antalya eskort
   

PHP ARTICLES

- Hackers Compromise PHP Sites to Launch Attac...
- Red Hat, Zend Form OpenShift PaaS Alliance
- PHP IDE News
- BCD, Zend Extend PHP Partnership
- PHP FAQ Highlight
- PHP Creator Didn't Set Out to Create a Langu...
- PHP Trends Revealed in Zend Study
- PHP: Best Methods for Running Scheduled Jobs
- PHP Array Functions: array_change_key_case
- PHP array_combine Function
- PHP array_chunk Function
- PHP Closures as View Helpers: Lazy-Loading F...
- Using PHP Closures as View Helpers
- PHP File and Operating System Program Execut...
- PHP: Effects of Wrapping Code in Class Const...

Developer Shed Affiliates

 


Dev Shed Tutorial Topics: