Retrieve data from multiple mySQL tables - php

Question

I will try and explain this as succinctly as possible as I'm quite new to this.
I have 3 tables: articles; categories; articles_to_categories
The complete Article class is below. The function getById is where I am aiming to pull the category through too.
<?php
/**
* Class to handle articles
*/
class Article
{
// Properties
/**
* #var int The article ID from the database
*/
public $id = null;
/**
* #var int When the article was published
*/
public $publicationDate = null;
/**
* #var string Full title of the article
*/
public $title = null;
/**
* #var string A short summary of the article
*/
public $summary = null;
/**
* #var string The HTML content of the article
*/
public $content = null;
/**
* Sets the object's properties using the values in the supplied array
*
* #param assoc The property values
*/
public function __construct( $data=array() ) {
if ( isset( $data['article_id'] ) ) $this->id = (int) $data['article_id'];
if ( isset( $data['publicationDate'] ) ) $this->publicationDate = (int) $data['publicationDate'];
if ( isset( $data['title'] ) ) $this->title = preg_replace ( "/[^\.\,\-\_\'\"\#\?\!\:\$ a-zA-Z0-9()]/", "", $data['title'] );
if ( isset( $data['summary'] ) ) $this->summary = preg_replace ( "/[^\.\,\-\_\'\"\#\?\!\:\$ a-zA-Z0-9()]/", "", $data['summary'] );
if ( isset( $data['content'] ) ) $this->content = $data['content'];
}
/**
* Sets the object's properties using the edit form post values in the supplied array
*
* #param assoc The form post values
*/
public function storeFormValues ( $params ) {
// Store all the parameters
$this->__construct( $params );
// Parse and store the publication date
if ( isset($params['publicationDate']) ) {
$publicationDate = explode ( '-', $params['publicationDate'] );
if ( count($publicationDate) == 3 ) {
list ( $d, $m, $y ) = $publicationDate;
$this->publicationDate = mktime ( 0, 0, 0, $m, $d, $y );
}
}
}
/**
* Returns an Article object matching the given article ID
*
* #param int The article ID
* #return Article|false The article object, or false if the record was not found or there was a problem
*/
public static function getById( $id ) {
$conn = new PDO( DB_DSN, DB_USERNAME, DB_PASSWORD );
$sql = "SELECT *, UNIX_TIMESTAMP(publicationDate) AS publicationDate FROM articles WHERE article_id = :id";
$st = $conn->prepare( $sql );
$st->bindValue( ":id", $id, PDO::PARAM_INT );
$st->execute();
$row = $st->fetch();
$conn = null;
if ( $row ) return new Article( $row );
}
/**
* Returns all (or a range of) Article objects in the DB
*
* #param int Optional The number of rows to return (default=all)
* #param string Optional column by which to order the articles (default="publicationDate DESC")
* #return Array|false A two-element array : results => array, a list of Article objects; totalRows => Total number of articles
*/
public static function getList( $numRows=1000000, $order="publicationDate DESC" ) {
$conn = new PDO( DB_DSN, DB_USERNAME, DB_PASSWORD );
$sql = "SELECT SQL_CALC_FOUND_ROWS *, UNIX_TIMESTAMP(publicationDate) AS publicationDate FROM articles
ORDER BY " . mysql_escape_string($order) . " LIMIT :numRows";
$st = $conn->prepare( $sql );
$st->bindValue( ":numRows", $numRows, PDO::PARAM_INT );
$st->execute();
$list = array();
while ( $row = $st->fetch() ) {
$article = new Article( $row );
$list[] = $article;
}
// Now get the total number of articles that matched the criteria
$sql = "SELECT FOUND_ROWS() AS totalRows";
$totalRows = $conn->query( $sql )->fetch();
$conn = null;
return ( array ( "results" => $list, "totalRows" => $totalRows[0] ) );
}
/**
* Inserts the current Article object into the database, and sets its ID property.
*/
public function insert() {
// Does the Article object already have an ID?
if ( !is_null( $this->id ) ) trigger_error ( "Article::insert(): Attempt to insert an Article object that already has its ID property set (to $this->id).", E_USER_ERROR );
// Insert the Article
$conn = new PDO( DB_DSN, DB_USERNAME, DB_PASSWORD );
$sql = "INSERT INTO articles ( publicationDate, title, summary, content ) VALUES ( FROM_UNIXTIME(:publicationDate), :title, :summary, :content )";
//PDO prepare escapes string like mysql_real_escape_string
//PDO Allows you to enforce a datatypye ie. Sting, Integer etc
$st = $conn->prepare ( $sql );
$st->bindValue( ":publicationDate", $this->publicationDate, PDO::PARAM_INT );
$st->bindValue( ":title", $this->title, PDO::PARAM_STR );
$st->bindValue( ":summary", $this->summary, PDO::PARAM_STR );
$st->bindValue( ":content", $this->content, PDO::PARAM_STR );
$st->execute();
$this->id = $conn->lastInsertId();
$conn = null;
}
/**
* Updates the current Article object in the database.
*/
public function update() {
// Does the Article object have an ID?
if ( is_null( $this->id ) ) trigger_error ( "Article::update(): Attempt to update an Article object that does not have its ID property set.", E_USER_ERROR );
// Update the Article
$conn = new PDO( DB_DSN, DB_USERNAME, DB_PASSWORD );
$sql = "UPDATE articles SET publicationDate=FROM_UNIXTIME(:publicationDate), title=:title, summary=:summary, content=:content WHERE id = :id";
$st = $conn->prepare ( $sql );
$st->bindValue( ":publicationDate", $this->publicationDate, PDO::PARAM_INT );
$st->bindValue( ":title", $this->title, PDO::PARAM_STR );
$st->bindValue( ":summary", $this->summary, PDO::PARAM_STR );
$st->bindValue( ":content", $this->content, PDO::PARAM_STR );
$st->bindValue( ":id", $this->id, PDO::PARAM_INT );
$st->execute();
$conn = null;
}
/**
* Deletes the current Article object from the database.
*/
public function delete() {
// Does the Article object have an ID?
if ( is_null( $this->id ) ) trigger_error ( "Article::delete(): Attempt to delete an Article object that does not have its ID property set.", E_USER_ERROR );
// Delete the Article
$conn = new PDO( DB_DSN, DB_USERNAME, DB_PASSWORD );
$st = $conn->prepare ( "DELETE FROM articles WHERE id = :id LIMIT 1" );
$st->bindValue( ":id", $this->id, PDO::PARAM_INT );
$st->execute();
$conn = null;
}
}
?>
What I need to do is output which multiple categories the article is in. Would I have to create another SQL statement within this function or can I do it in the one statement.
Table/Columns overview:
articles - id, publicationDate, title, summary, content
categories - id, categoryTitle
articles_to_categories - article_id, category_id
I hope this is enough information for someone to help me on my way.
Thanks.

Answer 1

I think you should modify your class and add
public $categorie = null; //because you will add new column to table article
and modify all the code that depends on it, add the column to your db. etc