Class Inheritance with SQLAlchemy

This is an example of "Joined Table Inheritance"

In this case the database will have three tables to segment "users":

1. A base users table which will store the columns in the model definition for User including the type column
2. A participant table which will store the participant id (which has a foreign key constraint to the user table) and the specified attributes in the participant model (e.g. email_address)
3. A host table which will store the host id (which has a foreign key constraint to the user table) and the specified attributes in the host model (e.g. website)

For example:

1. Create a new participant with a username=peter and email_address=peter@foo.bar.

• The user table will have a row with two columns: id: 1, and type: participant
• The participant table will have a new row with two columns id: 1 and email_address: peter@foo.bar

(Note: both id columns have the same value because of the foreign key constraint)

Querying

• Querying for all Users will return both Participant and Host objects
• Querying for all Participants will return ony Participant objects (and the same for Host)