Laravel form request validation on store and update use same validation
Stefan Bogdanescu
Founder & Senior Architect · 2026-06-29
# Mastering Conditional Validation: Handling Unique Constraints in Laravel Form Requests
As a senior developer working with the Laravel ecosystem, we often strive for DRY (Don't Repeat Yourself) principles. One of the most powerful tools for achieving this is the use of Form Requests. They provide a clean separation between business logic and request validation. However, even these elegant structures can present tricky challenges when dealing with stateful data, such as unique constraints during `store` versus `update` operations.
This post addresses a common pain point: how to apply the same validation rules across both creation (`store`) and modification (`update`) methods without letting an existing record's ID interfere with the uniqueness check.
## The Dilemma: Store vs. Update Uniqueness
You have created a single Form Request, say `PostRequest`, containing unique rules for a title or username. You intend to use this request for both creating a new post and updating an existing one.
The core problem arises from how the `unique` validation rule interacts with the presence of the primary key (ID) in your data:
1. **`store` Method:** When creating a new record, there is no existing ID to check against. The uniqueness validation works perfectly.
2. **`update` Method:** When updating an existing record, you submit the ID along with the new data. If the validation system checks for a unique value across *all* records, it sees the existing record and throws an error because the proposed new value would conflict with another entry (or itself, depending on the query scope), even if that conflict isn't logically intended during an update operation.
You want to ignore the uniqueness check specifically when an ID is present in the request payload, effectively telling Laravel: "If an ID exists, do not enforce the `unique` rule for this field."
## The Best Practice: Dynamic Validation Logic
The best practice here is to inject conditional logic directly into your Form Request to inspect the input data and adjust the validation rules dynamically based on the context of the request. We achieve this by leveraging conditional application of rules or custom logic within the `rules()` method.
Since standard Laravel validation doesn't offer a built-in "if ID exists, ignore unique rule" shortcut, we must manually check for the presence of the record identifier and adjust the rules accordingly.
### Implementation Example
Let's assume we are validating a `Post` model where the `title` must be unique.
#### 1. The Form Request (`app/Http/Requests/PostRequest.php`)
Instead of applying static rules, we will inspect the input data to decide if the uniqueness check should apply.
```php
*/
public function rules(): array
{
$rules = [
'title' => 'required|string|max:255',
// Add other general rules here...
];
// Check if the request is an update operation (i.e., ID is present in the request)
if ($this->isMethod('PUT') || $this->isMethod('PATCH')) {
// If it's an update, we relax the unique check for 'title'
// We still require the field to be present if we are updating (which it must be)
$rules['title'] = ['required', 'string', 'max:255'];
// Note: We explicitly remove the 'unique' rule here, or ensure a non-unique check is applied.
// For this example, we ensure only basic presence rules are enforced for updates.
} else {
// If it's a store operation (POST), enforce the unique constraint strictly
$rules['title'] = [
'required',
'string',
'max:255',
'unique:posts,title' // Enforce uniqueness for creation
];