SQLAlchemy is an open source python library which provides an abstraction over relational databases making them easier to work with. It provides a SQL expression language to generate SQL queries and has an object relational mapper that allows you to express database queries in terms of classes and relationships between them. Using SQLAlchemy has several advantages:
(1) Write generic python code to work across different database backends.
(2) Interact with the database through python objects instead of writing SQL.
(3) Expose data to powerful python libraries.
(4) It can support the features of the underlying database.
(5) It's free.