Conditional validation in Laravel - Step-by-Step Execution

Concept Flow - Conditional validation

Start Request

↓

Check if condition met?

No→Skip validation rule

Yes↓

Apply validation rule

↓

Validate all rules

↓

Return validation result

Laravel checks if a condition is true before applying a validation rule, then validates accordingly.

Execution Sample

Laravel

Validator::make($data, [
  'email' => 'required_if:contact_method,email',
  'phone' => 'required_if:contact_method,phone'
]);

Validates email or phone only if contact_method matches the field name.

Execution Table

Step	Input Data	Condition Check	Validation Rule Applied	Validation Result
1	{contact_method: 'email', email: '[e-mail]', phone: ''}	contact_method == 'email' (true)	email is required	email present - passes
2	{contact_method: 'email', email: '[e-mail]', phone: ''}	contact_method == 'phone' (false)	phone not required	phone empty - passes
3	{contact_method: 'phone', email: '', phone: '1234567890'}	contact_method == 'email' (false)	email not required	email empty - passes
4	{contact_method: 'phone', email: '', phone: '1234567890'}	contact_method == 'phone' (true)	phone is required	phone present - passes
5	{contact_method: 'email', email: '', phone: ''}	contact_method == 'email' (true)	email is required	email missing - fails
6	{contact_method: 'phone', email: '', phone: ''}	contact_method == 'phone' (true)	phone is required	phone missing - fails

💡 All validation rules checked based on conditions; validation passes or fails accordingly.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	After Step 6
contact_method	undefined	'email'	'email'	'phone'	'phone'	'email'	'phone'
email	undefined	'[e-mail]'	'[e-mail]'	''	''	''	''
phone	undefined	''	''	'1234567890'	'1234567890'	''	''
validation_result	undefined	pass	pass	pass	pass	fail	fail

Key Moments - 3 Insights

Why does the phone field validation skip when contact_method is 'email'?

Because the condition 'required_if:contact_method,phone' is false (contact_method is 'email'), so phone is not required (see execution_table step 2).

What happens if the required field is missing when its condition is true?

Validation fails because the rule applies and the field is empty (see execution_table steps 5 and 6).

Does Laravel validate fields without conditions always?

No, conditional rules apply only if their condition is true; otherwise, the rule is skipped (see execution_table steps 2 and 3).

Visual Quiz - 3 Questions

Look at the execution table, what is the validation result at step 5?

A Pass

B Skipped

C Fail

D Error

💡 Hint

Check the 'Validation Result' column at step 5 in the execution_table.

At which step does the phone field become required and passes validation?

A Step 2

B Step 4

C Step 5

D Step 6

💡 Hint

Look for when contact_method is 'phone' and phone is present in the execution_table.

If contact_method is 'email' but email is empty, what will happen?

A Validation fails

B Validation passes

C Validation skips email

D Validation error thrown

💡 Hint

Refer to step 5 in the execution_table where email is required but missing.

Concept Snapshot

Laravel Conditional Validation:
Use rules like 'required_if:field,value' to apply validation only when a condition is true.
If the condition matches, the rule runs; otherwise, it skips.
This helps validate fields dynamically based on other inputs.
Example: 'email' => 'required_if:contact_method,email'.

Full Transcript

This visual execution shows how Laravel applies conditional validation rules. It starts by checking if a condition is true, such as if 'contact_method' equals 'email'. If true, Laravel applies the validation rule like 'required' to the 'email' field. If false, it skips that rule. The execution table traces different input cases, showing when fields are required or not and whether validation passes or fails. Variables like 'contact_method', 'email', and 'phone' change per step, affecting validation results. Key moments clarify why some fields skip validation and why missing required fields cause failure. The quiz tests understanding by asking about validation results at specific steps. The snapshot summarizes how to use conditional validation rules in Laravel simply and effectively.