storing array in a sql database - php

Question

I started getting into arrays and don't quite get it to work well. I'm used to work with explode/implode functions but I though arrays would make my life easier in this part of the code. Here is the function called:
function save_event($event_items = NULL) {
include 'connect.php';
$now = date("Y-m-d H:i:s");
$sqla = "
INSERT INTO `event`(`event_items`, `event_entered`)
VALUES ('$event_items','$now')";
$resulta = mysqli_query($link, $sqla);
if(!$resulta)
{
echo '<br/>An error occurred while inserting your data. Please try again later.<br/>';
}
else
{ echo 'this is the variable to be stored:<br/>';
print_r($event_items);
$sql = "SELECT * FROM `event` WHERE event_entered = '".$now."'";
$result = mysqli_query($link, $sql);
if($result)
{ while($row = mysqli_fetch_assoc($result))
{ echo '<br/></br>This is the value of the database:<br/>';
print_r ($row['event_items']);
}
}
}
}
This function prints:
this is the variable to be stored:
Array( [0] => Array ( [item] => Powered Speaker [note] => [quantity] => 2 [price] => 200.00 [category] => Audio ) [1] => Array ( [item] => Wireless Microphone [note] => Lavalier [quantity] => 3 [price] => 175.00 [category] => Audio ))
This is the value of the database:
Array
In phpMyAdmin, all I see in the column event_items is the word Array.
Additional info:
I have a table called Groups, each group will have one or multiple orders (another table called Order) and each order will have also one or multiple events (another table). Lastly, each event will have one or multiple items (each item with its corresponding price, quantity, note and category), which are stored in one (or many) columns in the Event table.

Answer 1

Don't try to store an array in one field. You should store each item in the array as it's own row in a related table.

Answer 2

You are trying to insert multiple values in a single database record, this is not impossible but it's also not recommended in general.
The main reason someone would do this would be for optimization, which is not at all something you should worry about for now.
What you really want to do is review your database schema, if you wish to store an array of value, you need to create a new row (record) for each of those. This might necessitate the creation of another table, depending on what you want to do.

Answer 3

You could serialize your array with the serialize() function.
Example:
serialize($event_items);
Generates a storable representation of a value.
This is useful for storing or passing PHP values around without losing
their type and structure.
http://php.net/manual/en/function.serialize.php