Trouble creating parent-child relationship between two database tables using php codeigniter - php

Question

I have two databases tables called article_category and article_case. They are supposed to be combined in a webpage as below:
Article category[title]
Article category[description]
Article case[title]
Article case[contents]
Article case[title]
Article case[contents]
This should repeat itself using foreach until all article categories are populated on the page.
Each article_case will also use foreach, but it has to respect its 'category_id' value which matches the 'id' in article_category .
I'm having trouble filtering the article_case table so that it only picks up rows from its parent 'category_id'.
This is my current php code (which only makes an array of each table):
$this->db->select( "id,title,description" );
$this->db->from( 'article_category' );
$query_article_category = $this->db->get_compiled_select();
$query = $this->db->query( $query_sustainability_category . 'ORDER BY sort ASC ' );
foreach ($query->result_array() as $val) {
$data['article_category_posts'][$val['id']] = $val;}
$this->db->select( "id,category_id,title,contents" );
$this->db->from( 'article_case' );
$query_article_case = $this->db->get_compiled_select();
$query = $this->db->query( $query_article_case);
$data[ 'article_cases' ] = $query->result_array();
And here is my html:
<?php foreach ($article_category_posts as $key => $val) { ?>
<section>
<h2><?php echo $val['title']; ?></h2>
<p><?php echo $val['description']; ?></p>
</section>
<?php foreach ($article_cases as $key => $val) { ?>
<section>
<h3><?php echo $val['title']; ?></h3>
<p><?php echo $val['contents']; ?></p>
</section>
<?php } ?>
<?php } ?>
The current setup will input all article_cases disregarding the category_id.
How can I use foreach while assigning each article_case to their respective article_cateogry?

Answer 1

This would generate unnecessary amount of queries to the DB server.
The rly basic approach would be:
select all categories (as you have) SELECT * FORM a_category
for each category select cases SELECT * FROM a_case WHERE category_id = {$category['id']}
The second one is to combine the categories and cases right in the query with join and adjust the resulting data in php:
SELECT cat.title, cat.description, case.id AS case_id, case.category_id, case.title, case.content
FROM a_case case
INNER JOIN a_category cat ON cat.id = case.category_id

Answer 2

You can use a query to get all the records of article_case with related article_category.
group the query result by category_id.
$this->db->select("cat.title,cat.description,case.category_id,
case.title AS case_title, case.contents" );
$this->db->from( 'article_category cat');
$this->db->join('article_case case','case.category_id=cat.id');
$result=$this->db->get()->result_array();
$result_group = array_group_by($result, 'category_id');
array group by function
function array_group_by(array $array, $key)
{
if (!is_string($key) && !is_int($key) && !is_float($key) && !is_callable($key)) {
trigger_error('array_group_by(): The key should be a string, an integer, or a callback', E_USER_ERROR);
return NULL;
}
$func = (is_callable($key) ? $key : NULL);
$_key = $key;
// Load the new array, splitting by the target key
$grouped = [];
foreach ($array as $value) {
if (is_callable($func)) {
$key = call_user_func($func, $value);
} elseif (is_object($value) && isset($value->{$_key})) {
$key = $value->{$_key};
} elseif (isset($value[$_key])) {
$key = $value[$_key];
} else {
continue;
}
$grouped[$key][] = $value;
}
// Recursively build a nested grouping if more parameters are supplied
// Each grouped array value is grouped according to the next sequential key
if (func_num_args() > 2) {
$args = func_get_args();
foreach ($grouped as $key => $value) {
$params = array_merge([$value], array_slice($args, 2, func_num_args()));
$grouped[$key] = call_user_func_array('array_group_by', $params);
}
}
return $grouped;
}
in view you can show as below
<?php foreach ($result_group as $key => $cat_result) { ?>
<section>
<h2><?php echo $cat_result[0]['title']; ?></h2>
<p><?php echo $cat_result[0]['description']; ?></p>
<div class="box-bd-doted">
</section>
<?php foreach ($cat_result as $key => $val) { ?>
<section>
<h3 style="color:red"><?php echo $val['case_title']; ?></h3>
<p><?php echo $val['contents']; ?></p>
</section>
<?php }
}
?>