Why Reading and writing settings in Wordpress? - Purpose & Use Cases

The Big Idea

Discover how WordPress keeps your site settings safe and simple to change!

The Scenario

Imagine you have a WordPress site and want to change the site title or enable a feature. You try to do this by editing files directly or changing database values manually.

The Problem

Manually editing files or database is risky, slow, and can break your site if you make a mistake. It's hard to keep track of changes and update settings safely.

The Solution

WordPress provides functions to read and write settings safely. These functions handle saving, retrieving, and validating settings so you don't have to worry about breaking things.

Before vs After

✗ Before

$wpdb->query("UPDATE wp_options SET option_value='My Site' WHERE option_name='blogname'");

✓ After

update_option('blogname', 'My Site');
$site_title = get_option('blogname');

What It Enables

This lets you easily manage site settings in a safe, consistent way that works with WordPress's system and plugins.

Real Life Example

When you change the site title in WordPress admin, it uses these functions behind the scenes to save your new title without risking errors.

Key Takeaways

Manual setting changes are risky and error-prone.

WordPress functions safely read and write settings.

This makes managing site options easy and reliable.

Practice

1. Which WordPress function is used to read a saved setting from the database?

easy

A. get_option

B. save_option

C. set_option

D. read_option

Solution

1. Step 1: Understand the purpose of each function

   get_option is the WordPress function designed to retrieve saved settings. The others are not valid WordPress functions.

2. Step 2: Confirm the correct function for reading settings

   Since get_option reads the saved option value, it is the correct choice.

3. Final Answer:

   get_option -> Option A

4. Quick Check:

   Read settings = get_option [OK]

Hint: Remember: get_option reads, update_option writes [OK]

Common Mistakes:

• Confusing get_option with update_option
• Using non-existent functions like save_option
• Thinking set_option reads settings

2. Which of the following is the correct syntax to update a setting named 'site_color' to 'blue'?

easy

A. update_option('site_color', 'blue');

B. update_option('site_color' => 'blue');

C. get_option('site_color', 'blue');

D. set_option('site_color', 'blue');

Solution

1. Step 1: Identify the correct function and syntax for updating

   The function to update a setting is update_option, which takes two parameters: the option name and the new value.

2. Step 2: Check the syntax of each option

   update_option('site_color', 'blue'); correctly uses update_option('site_color', 'blue');. update_option('site_color' => 'blue'); uses an incorrect array syntax. get_option('site_color', 'blue'); uses get_option which reads, not writes. set_option('site_color', 'blue'); uses a non-existent function.

3. Final Answer:

   update_option('site_color', 'blue'); -> Option A

4. Quick Check:

   Update syntax = update_option(name, value) [OK]

Hint: update_option needs two arguments: name and value [OK]

Common Mistakes:

• Using get_option to update values
• Passing arguments as an array instead of separate parameters
• Using non-existent set_option function

3. What will be the output of this code snippet?

$color = get_option('site_color', 'red');
echo $color;

Assuming 'site_color' is not set in the database.

medium

A. site_color

B. null

C. '' (empty string)

D. red

Solution

1. Step 1: Understand get_option default value behavior

   If the option 'site_color' does not exist, get_option returns the default value provided as the second argument, here 'red'.

2. Step 2: Determine the output of echo

   Since 'site_color' is not set, $color will be 'red', so echo outputs 'red'.

3. Final Answer:

   red -> Option D

4. Quick Check:

   Missing option returns default value [OK]

Hint: get_option returns default if option missing [OK]

Common Mistakes:

• Assuming get_option returns empty string if missing
• Confusing option name with value
• Expecting null instead of default

4. Identify the error in this code snippet:

update_option('background_color');

medium

A. Function name should be get_option to update

B. update_option cannot update 'background_color'

C. Missing the new value parameter in update_option

D. update_option requires three parameters

Solution

1. Step 1: Check update_option function parameters

   update_option requires two parameters: the option name and the new value to set.

2. Step 2: Identify the missing parameter

   The code only passes the option name, missing the new value, causing an error.

3. Final Answer:

   Missing the new value parameter in update_option -> Option C

4. Quick Check:

   update_option needs name and value [OK]

Hint: update_option always needs two arguments [OK]

Common Mistakes:

• Passing only one argument to update_option
• Confusing get_option with update_option
• Thinking update_option needs three parameters

5. You want to save a user preference 'font_size' only if it is a positive integer. Which code snippet correctly updates the setting safely?

hard

A. update_option('font_size', $_POST['font_size']);

B. $size = intval($_POST['font_size']);
if ($size > 0) {
update_option('font_size', $size);
}

C. if ($_POST['font_size']) {
update_option('font_size', $_POST['font_size']);
}

D. $size = $_POST['font_size'];
update_option('font_size', $size > 0 ? $size : 12);

Solution

1. Step 1: Validate and sanitize the input

   $size = intval($_POST['font_size']);
   if ($size > 0) {
     update_option('font_size', $size);
   }

   uses intval to convert input to integer and checks if it is positive before saving.

2. Step 2: Confirm safe update of option

   Only if the value is positive does it call update_option, preventing invalid data.

3. Final Answer:

   $size = intval($_POST['font_size']);
   if ($size > 0) {
   update_option('font_size', $size);
   } -> Option B

4. Quick Check:

   Validate input before update_option [OK]

Hint: Always validate input before update_option [OK]

Common Mistakes:

• Saving raw user input without validation
• Using update_option without checking value
• Assuming non-empty input is always valid