getorcreate

Get or create is a programming pattern used by many data access layers and object-relational mappers. It attempts to retrieve an object that matches given lookup criteria; if such an object is found, it is returned. If not, a new object is created with the provided defaults and saved to the database. The operation commonly returns both the object and a boolean indicating whether it was created.

Most frameworks provide a get_or_create function or equivalent. Examples include Django's Manager.get_or_create, SQLAlchemy's get_or_create approach, Rails' find_or_create_by, and Sequelize's findOrCreate. The API varies, but the intent is the same: a single call that yields an existing object or creates one atomically.

Typical use cases include ensuring a unique record for a key such as a user email or account id, idempotent seed scripts, and creating related resources without duplicating entries. It is often employed when the cost of a separate lookup and create would be undesirable or error-prone.

Concurrency and data integrity considerations are central to get or create. Without proper isolation, two concurrent operations could race and produce duplicates. Mitigations include enforcing a unique constraint on the lookup fields, wrapping the operation in a transaction, or using database-level upsert/merge capabilities. Some ORMs implement get_or_create atomically, while others require explicit handling of potential race conditions.

Example (conceptual): obj, created = Model.get_or_create(name='Alice', defaults={'email': '[email protected]'})