如何访问WordPress插件变量/ MySQL数据？

Question

I have a plugin that is an extension to woocommerce. This plugin stores information under the MySQL Table "wp_woocommerce_order_itemmeta". Under the column "meta_key", there is "_wc_deposit_meta". Next to the column "meta_key" I have "meta_value". Under the "meta_value" you find a:5:{s:6:"enable";s:3:"yes";s:7:"deposit";d:197.67000000000001591615728102624416351318359375;s:9:"remaining";d:401.32999999999998408384271897375583648681640625;s:5:"total";d:599;s:5:"ratio";d:1;} . While learning PHP I have never came across a value like this. Could someone explain what this value is and how do I access the value for "deposit". Is this just another example of a multidimensional array?

I have been trying to access this value by $my_order = $order->get_items(); in my functions.php, which is returning an array. I see the correct array called "_wc_deposit_meta" with this weird value that I do not know how to access because of the commas and colons.

Sorry for the noob question but I have been trying to research this buy could not find a simple black and white answer. If someone could point me in the right direction, I would be very appreciative.

Answer 1

The value that you're looking at has been serialized() and stored in the database. Simply take that variable and use unserialize() on it, like so:

$myVal = unserialize($databaseColumn);

1. serialize
2. unserialize

Answer 2

When WordPress needs to store multi-dimensional data into a field it applies PHP's serialize() function to convert the data into a storable string, then unserialize() when reading the value to return it to it's proper data structure.

The anatomy of serialized data definitions are described in the first comment on PHP's serialize() documentation:

• String: s:[size]:[value];
• Integer: i:[value];
• Double: d:[value];
• Boolean: b:[value]; (does not store "true" or "false", does store '1' or '0')
• Null: N;
• Array: a:[size]:{[key definition];[value definition];(repeated per element)}
• Object: O:[strlen(object name)]:[object name]:[object size]:{s:[strlen(property name)]:[property name]:[property definition];(repeated per property)}

More specifically, WordPress uses it's own maybe_serialize() and maybe_unserialize() wrappers to mitigate the chance of (un)serializing when not necessary.

In the particular serialized data you are working with, your deposit is represented by the key/value definitions s:7:"deposit";d:197.67000000000001591615728102624416351318359375; . To alter your deposit value by hand, you would modify the double after d: . To modify the value programmatically in WordPress, use the Metadata API to query the field using a "get" function (which will implicitly unserialize it), modify the value of the 'deposit' field in the returned associative array, then save the new value using an "update" function from the Metadata API.