Primary keys - the basics
Single-column primary keys
Multicolumn primary keys
Auto-increment columns and sequences
Instruction
Alright. As you can see, it's possible to use a varchar column as the primary key, but it is not advisable.
Primary keys are important, so we mark which column the primary key is in ERD diagrams too. We usually use the abbreviation PK:
Exercise
Try to create the database using the following ERD diagram:
Stuck? Here's a hint!
Type
CREATE TABLE account ( user_id int PRIMARY KEY, first_name varchar(32), nickname varchar(24), description text );
