Proper way to establish database connection in python

I have a script with several functions that all need to make database calls. I'm trying to get better at writing clean code rather than just throwing together scripts with horrible style. What is generally considered the best way to establish a global database connection that can be accessed anywhere in the script but is not susceptible to errors such as accidentally redefining the variable holding a connection. I'd imagine I should be putting everything in a 开发者_JAVA技巧module? Any links to actual code would be very useful as well. Thanks.

If you are working with Python and databases, you cannot afford not to look at SQLAlchemy:

SQLAlchemy is the Python SQL toolkit and Object Relational Mapper that gives application developers the full power and flexibility of SQL.

It provides a full suite of well known enterprise-level persistence patterns, designed for efficient and high-performing database access, adapted into a simple and Pythonic domain language.

I have built very complex databases with a surprisingly small amount of code (a few hundred lines). The schema definition is almost self-documenting, the objects used for the Object Relational Mapper are Plain Old Python Objects (i.e., what you already have), and the querying API is almost obvious. In addition, the documentation is excellent: many online examples, fully documented API, and an O'Reilly book which, while far from perfect, does take you from zero to dangerous in a few evenings.

If you don't want to use the Object Relational Mapper, you can always fall back to plain connections and literal SQL. Also, the code is portable and database independent (the same code will work with MySQL, Oracle, SQLite, and other database managers).

The Session object will automatically take care of the pooling (what you mention as your concern).

The best way to understand its power is probably to follow the tutorials obtained in the first result page of the Google query sqlalchemy tutorial.

Use a model system/ORM system.