Django null blank field

Peter Pik Peter Pik You're mixing up model field arguments with form field arguments. Add a comment. Active Oldest Votes. Przemek Przemek 1 1 gold badge 7 7 silver badges 22 22 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password.

Post as a guest Name. Email Required, but never shown. The Overflow Blog. Things can be far more complex than this, but this knowledge will guide us through the rest of the tutorial. Easily the most important method when working with Django models and the underlying QuerySets is the filter method, which allows you to generate a QuerySet of objects that match a particular set of filtered parameters.

We can quickly see that our database contains 20 books in total by using the count method:. Now, by using filter , we can retrieve a QuerySet of just those books that were published within the last 90 days period, like so:.

With filter , we can determine that merely 3 of our 20 total books were published within the last 90 day period. Similar to the filter method but acting as the mirror opposite is the exclude method. As the name implies, exclude functions by excluding all the matches from the supplied parameters, and returning the QuerySet that remains.

Now that we understand the basics of using filter and exclude to retrieve a modified QuerySet in Django, we can use these methods to look for field values that are either empty or NULL. As discussed above, there are a number of potential field lookups that can be used with filter and exclude , and when working with field values that are NULL , the field lookup of choice should be isnull.

Models typically make up the foundation of most Django projects. Models not only define the structure of the database, each model is the mechanism for accessing and modifying the data stored in the database table represented by the model. Models are also generally responsible for any behaviors of the data and for validating data to protect the quality of the data in the database.

The most obvious part of any Django model is the list of fields. Each field in a model is related to a column or attribute in the database table associated with the model. Fields have two options that can be confusing to many developers that are new to the framework. The two options are null and blank.