Persistent structured storage.
WHEN TO USE ONE
Data that outlives the program Data several processes access More data than fits comfortably in memory Anything needing reliable updates
WHAT PYTHON INCLUDES
A lightweight file-based database, requiring nothing installed.
Excellent for small applications and local storage.
WHAT ELSE IS COMMON
Server databases, for larger applications and shared access.
On our hosting, MySQL or MariaDB through cPanel.
THE ESSENTIAL RULE
Never build queries by joining strings containing user input.
WHY
That is how injection vulnerabilities occur.
WHAT TO DO INSTEAD
Use parameterised queries, where values are passed separately from the statement.
Always. Without exception.
WHAT ELSE TO DO
Close connections Handle failures Use transactions where several changes must succeed together
WHAT AN ORM PROVIDES
A layer mapping database rows to Python objects.
Convenient for larger applications, and unnecessary for simple scripts.
WHAT TO STORE SECURELY
Database credentials, outside the code.
