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Why Django Model.Save() Doesn’t Trigger Full_clean() – Explained

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One of the most critical aspects of developing a web application is to ensure that the data submitted by users is valid and safe. A developer must validate the incoming data before storing it in a database to prevent any security breaches or data corruption. In Django, the method is used to save data to the database. However, there’s a catch – the method doesn’t trigger full_clean().

For those who are new to Django, full_clean() is a method that validates the model instance and raises a validation error if any of the fields are invalid. This method is triggered automatically when a form is validated, but it must be called manually when saving data directly with the method. But why doesn’t Django execute full_clean() when using

The reason is simple – Django designed it this way to provide flexibility to the developers. full_clean() is a costly process, and it can add significant overhead to the development process. Many times, the validation checks can be skipped if the developer is confident that the data being saved is from a trusted source or has already been cleaned earlier in the development process. Therefore, Django only triggers full_clean() when a form is validated or when invoked explicitly.

Before we conclude, it’s worth noting that you should always run validation checks when saving user-input data to the database. Skipping the validation process can result in security vulnerabilities or data corruption. Thankfully, Django provides several ways to validate the data before saving it to the database. So, if you want to learn more, read the article through the link provided below to understand the different approaches you can take to validate your data and keep your web application secure.

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“Why Doesn’T Django’S Model.Save() Call Full_clean()?” ~ bbaz


Django Model.Save() method is used to save the model data into the database. It is an important function as it helps in persisting the data. However, there is a common misconception that calling the save() method of a model object automatically triggers the full_clean() method of the model. In this blog, we will explore why Django Model.Save() doesn’t trigger full_clean() and understand its implications.

Django Save() Method

The save() method of Django models saves the instance of the model to the database. This method can be overridden to add any custom logic that needs to be executed when the instance is saved. By default, Django provides a simple implementation of the save() method which takes care of most use cases.

The Signature of the Save() Method

The Signature of the save() method is –

“`pythondef save(self, force_insert=False, force_update=False, using=None, update_fields=None):“`

Full Clean() Method

The full_clean() method of Django models is used to perform validation on the model fields. It validates all the fields of the model and populates the field.errors dictionary with any errors encountered. If there are no errors, then the instance is considered valid.

Invoking full_clean()

full_clean() method can be invoked manually by the developer to perform validation on the instance. It is also called automatically during the ModelForm validation process when form’s is_valid() method is called.

Why Save() Doesn’t Trigger Full_clean()

By default, the save() method of Django models does not trigger full_clean(). However, this behavior can be changed by implementing a custom save() method and calling full_clean() method explicitly.

The primary reason why save() doesn’t trigger full_clean() by default is that it can be an expensive operation. Performing validation on the entire instance can take time, especially when there are many fields, or the fields contain complex validation logic.

Comparison Table

save() full_clean()
Saves the instance to the database. Performs validation on the model fields.
Can be customized to add custom behaviors. Cannot be customized as it is provided by Django.
Does not trigger full_clean() by default. Needs to be called explicitly to perform validation.
May result in saving invalid data in the Database. Ensures that only valid data is saved in the database.


It is important to note that while full_clean() may cause some performance overhead, it is necessary to ensure that only valid data is saved in the database. Invalid data can lead to incorrect results and inconsistencies in the application. Developers should take care to either call full_clean() explicitly in their save() method or use ModelForms to perform automatic validation.

In conclusion, Django Model.Save() does not trigger Full_clean() by default, primarily due to performance reasons. While this can result in saving invalid data, developers can customize the save() method to include full_clean() if necessary. It is important to ensure that all data saved in the database is valid to prevent issues later on.

Dear blog visitors,

Thank you for taking the time to read our article on why Django doesn’t trigger full_clean(). We hope that you have found it informative and have learned something new about Django.

In summary, we have explained that the reason why does not trigger full_clean() by default is that it is designed to allow for flexibility in how developers want to handle data validation. By separating the save() and full_clean() methods, developers can customize their own validation process to suit their specific needs.

Furthermore, we have provided some tips on how to implement your own custom save() method that includes full_clean() if you still wish to use this functionality. We have also highlighted the potential downsides of using full_clean() in every save() method and advised on best practices.

We hope that we have been able to clarify any confusion around this topic and that you can now feel confident in using Django’s save() and full_clean() methods effectively in your projects.

Thank you for reading, and we look forward to providing you with more valuable insights into Django and other technologies in the future.

Best regards,

The [Name of blog/company] team

Why Django Model.Save() Doesn’t Trigger Full_clean() – Explained

Django is a popular web framework used for creating robust and scalable web applications. One of the key features of Django is its built-in Object Relational Mapping (ORM) system, which allows developers to interact with their application’s database using Python objects instead of SQL queries.

One aspect of the Django ORM that can be confusing for developers is the behavior of the method. Specifically, many developers are surprised to learn that calling save() on a model instance does not automatically trigger the full_clean() method, which is responsible for validating the model’s fields and raising validation errors if necessary.

People also ask about why Django Model.Save() Doesn’t Trigger Full_clean() – Explained:

  1. What is the purpose of the full_clean() method?
  2. The full_clean() method is used to validate a model’s fields and raise validation errors if necessary. This method is called automatically when a form based on the model is validated, but it must be called manually if you want to validate a model instance outside of a form context.

  3. Why doesn’t automatically call full_clean()?
  4. The reason that does not automatically call full_clean() is that there are situations where you may want to save a model instance without validating it first. For example, if you are populating a database with initial data, you may not want to validate each record individually.

  5. How can I ensure that my model is validated before saving?
  6. If you want to ensure that your model is validated before saving, you can call full_clean() manually before calling save():

  7. What is the difference between and Model.validate_and_save()?
  8. Model.validate_and_save() is not a built-in method in Django. It is a custom method that you can define on your models if you want to ensure that validation is always performed before saving. For example:

    class MyModel(models.Model):    # fields go here    def validate_and_save(self):        self.full_clean()

By defining a custom validate_and_save() method like this, you can ensure that all instances of your model are validated before they are saved to the database.