In the terminal, type
mysql -u root
create database <name>;
show databases;
use <name>;
create table parents (
parent_id int unsigned auto_increment primary key,
surname varchar(50) not null,
proper_name varchar(50) not null
) engine=innodb;
show tables;
describe <table name>;
drop table <name>
alter table child add gender varchar(1) not null;
alter table child drop gender;
alter table child rename column proper_name to last_name;
// 1. create the new column
alter table sessions add coach_id int unsigned not null;
// 2. create the foregin key
alter table sessions add constraint fk_coach_id foreign key (coach_id) references coaches(coach_id);