How to check the value of a string?

Question

PostgreSQL

I need to remember the gender of a person, so I add another column.
Because there will not be more than 2 genders on the site I want to check the line for a match (male or famale).

In my opinion it should look like this:

ALTER TABLE product ADD COLUMN gender VARCHAR(6) CHECK ('male' or 'female');

I can't figure out the CHECK syntax, please help.

Answer 1

Using VARCHAR(6) for the gender field is not rational. Use ENUM('mail'. 'femail') or even BOOLEAN

Answer 2

https://habr.com/ru/post/353556/