Introduction
Defining columns with DEFAULT
Adding DEFAULT to existing tables
Instruction
Excellent! Now we have a small surprise for you. Do you remember sequences? We can actually link them to columns – let's try it! We'll use the DEFAULT constraint. Here it is with PostgreSQL syntax:
CREATE TABLE board_game (
id integer DEFAULT nextval('my_sequence') PRIMARY KEY
);
Here is the standard SQL syntax:
CREATE TABLE board_game ( id integer DEFAULT NEXT VALUE FOR my_sequence PRIMARY KEY );
Not too complicated, is it?
Exercise
We'll build a DEFAULT together with a sequence. First, let's create a sequence. A sequence with the name my_sequence which starts at 10 and adds 2 each time would look like this:
CREATE SEQUENCE my_sequence START WITH 10 INCREMENT BY 2;
Your job is to create a sequence called id_seq, which starts at 1 and increments by 1.
