FOREIGN KEYS

A VERY IMPORTANT TOPIC: FOREIGN KEYS

Details: https://www.sqlitetutorial.net/sqlite-foreign-key/

Q: What are they for? A: For creating logical relationships between tables.

For example:

CREATE TABLE suppliers (
    supplier_id integer PRIMARY KEY,
    supplier_name text NOT NULL,
    group_id integer NOT NULL
    FOREIGN KEY (group_id)
        REFERENCES supplier_groups(group_id)
);

CREATE TABLE supplier_groups (
    group_id integer PRIMARY KEY,
    group_name text NOT NULL );