5Primary_Key.sql

drop table customers;
drop table items;
drop table companies;

 
 create table customers(
 customer_id int , 
 first_name varchar(255), 
 last_name varchar(255), 
 email_address varchar(255),  
 number_of_complaints int,
 primary key (customer_id)
 );
 
 create table items(
 item_code varchar(255),
 unit varchar(255),
 unit_price numeric(10, 2),
 company_id varchar(255),
 primary key (item_code)
 );
 
 create table companies(
company_id varchar(255),  
company_name varchar(255),  
headquarters_phone_number int(12),
primary key (company_id)
);