Reading and writing settings in Wordpress - Step-by-Step Execution

Concept Flow - Reading and writing settings

Start

↓

Call get_option('setting_name')

↓

Retrieve value from DB

↓

Use value in code

↓

Call update_option('setting_name', new_value)

↓

Save new_value to DB

↓

Confirm save success

↓

End

This flow shows how WordPress reads a setting from the database using get_option, uses it, then writes a new value back with update_option.

Execution Sample

Wordpress

<?php
$value = get_option('my_setting');
if ($value === false) {
  update_option('my_setting', 'default');
}
?>

This code reads a setting 'my_setting', and if it doesn't exist, writes a default value.

Execution Table

Step	Function Called	Input	Action	Output/Result
1	get_option	'my_setting'	Look for 'my_setting' in DB	Returns false (not found)
2	Condition	if ($value === false)	Check if value exists	True, value missing
3	update_option	'my_setting', 'default'	Save 'default' to DB under 'my_setting'	Returns TRUE (success)
4	End	-	Setting now saved	-

💡 Setting 'my_setting' was missing, so default value was saved and process ends.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
$value	undefined	false	false	false	false

Key Moments - 2 Insights

Why does get_option return false sometimes?

Because the setting does not exist yet in the database, as shown in execution_table step 1.

What happens if update_option is called with a new setting?

It creates the setting in the database with the given value, as shown in execution_table step 3.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of $value after step 1?

A TRUE

B false

C 'default'

D Undefined

💡 Hint

Check the 'Output/Result' column in step 1 of the execution_table.

At which step does the setting get saved to the database?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look for update_option calls in the execution_table.

If get_option returned a value instead of false, what would happen?

A The condition would be false and update_option would not run

B update_option would still run

C The code would error out

D The value would be deleted

💡 Hint

Check the condition check in step 2 of the execution_table.

Concept Snapshot

Reading and writing settings in WordPress:
- Use get_option('name') to read a setting.
- Returns false if setting missing.
- Use update_option('name', value) to save or update.
- update_option creates setting if missing.
- Always check get_option result before update.

Full Transcript

This visual execution shows how WordPress reads and writes settings using get_option and update_option. First, get_option tries to find the setting in the database. If it returns false, it means the setting does not exist yet. Then, update_option is called to save a default value. This creates the setting in the database. The variable $value starts undefined, becomes false after get_option, and remains false since update_option does not change it directly. Understanding this flow helps beginners manage WordPress settings safely.

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