In this chapter, we will build our first fully functional, database-backed application. This application, codenamed Snap, will allow users to create an account with a username and password. Users will be allowed to login, logout, add and list the so-called semiprivate snaps of text that can be shared with others.

For this chapter, you should be familiar with at least one of the following relational database systems: PostgreSQL, MySQL, or SQLite. Additionally, some knowledge of the SQLAlchemy Python library, which acts as an abstraction layer and object-relational mapper for these (and several other) databases, will be an asset. If you are not well versed in the usage of SQLAlchemy, fear not. We will have a gentle introduction to the library that will bring new developers up to speed and serve as a refresher for the more experienced.

From this point on, in the book, the SQLite database will be our relational database of choice. The other...