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How to fix ‘django.db.backends.dbapi.DuplicateKeyError’

Last Updated : 06 Dec, 2023
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In this article, we will introduce you to ‘django.db.backends.dbapi.DuplicateKeyError’ and provide possible solutions for resolving it.

What is ‘django.db.backends.dbapi.DuplicateKeyError’ ?

Django.db.backends.dbapi.DuplicateKeyError‘ is an error that occurs in our Django project when we attempt to save an object with unique fields, but an object with the same unique values already exists in the database. This typically happens when we are trying to recreate an object with identical values that were previously saved.

Example

django.db.backends.dbapi.DuplicateKeyError'

Integrity errors, such as violating a unique constraint, can also trigger this error. In the following sections, we will explore how to address and resolve this issue effectively

Common Reasons

  • If you are trying to save an object with duplicate unique fields.
  • You may have different processes running simultaneously. in this case it may happen on same time more than 1 process trying to save an object with the same unique value field.
  • Occurrence of other integrity errors, such as violating foreign key constraints or validation rules within the database, leading to the ‘DuplicateKeyError.

How to fix ‘django.db.backends.dbapi.DuplicateKeyError’ ?

Method 1: Check if the object already exists before creation or saving

One effective practice to prevent the ‘django.db.backends.dbapi.DuplicateKeyError‘ is to check whether the object with a unique value already exists before attempting to create or save it. This approach is particularly useful when you are uncertain whether an object with the same unique field value has been created before. Here is an example of how you can use try and catch blocks to handle this scenario and avoid the error:

Python3




try:
    # Try to get the product with the given name
    product = Product.objects.get(product_name="xiomi_mi12")
except Product.DoesNotExist:
    # Handle the case when the product does not exist
    # Create the product if it doesn't exist
    Product.objects.create(product_name="xiomi_mi12")


Method 2: Use Get( ) or Create( ) to Retrieve data

Django’s Object-Relational Mapping (ORM) provides a convenient method called get_or_create() that simplifies the process of checking if an object with specific attributes already exists in the database. If it doesn’t exist, it creates the object; if it does exist, it retrieves the existing object. This method is a powerful tool to avoid encountering the ‘django.db.backends.dbapi.DuplicateKeyError.’

Python3




obj, created = Product.objects.get_or_create(
    product_name="samsung_f14",
    product_tag="smartphones"
)
 
if created:
    # New object was created
    # Perform actions specific to a newly created object
else:
    # Existing object was retrieved
    # Perform actions specific to an existing object


Method 3: Handle Integrity Errors

If you continue to encounter the issue, it’s possible that constraint errors may be at play. In such cases, treat the error as an integrity issue and scrutinize your model definitions. These are all the potential reasons for encountering the error and how to resolve it with these various fixes. I hope you find this article helpful.

Python3




try:
    product = Product.objects.get(product_tag="smartphone")
except Product.DoesNotExist:
    print("Product not found")
    # Handle the case when the product does not exist




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