We have 2 tables with dependent data

One-to-many from contractor_categories to contractor_subcategories


Dropdown fields use the following SQL queries

SELECT id, name FROM contractor_categories
 
SELECT id, name, contractor_categories_id FROM contractor_subcategories

 

DB setup

create table contractor_categories (id int, name varchar(100));
create table contractor_subcategories (id int, name varchar(100), contractor_categories_id int);

insert into contractor_categories values(1, 'Software Development');
insert into contractor_categories values(2, 'Cleaning');
insert into contractor_categories values(3, 'Security');
 
insert into contractor_subcategories values(4, 'General cleaning', 2);

insert into contractor_subcategories values(5, 'Entrance', 3);
insert into contractor_subcategories values(6, 'Night shifts only', 3);
insert into contractor_subcategories values(7, 'Basement and perimeter', 3);

 

Form configuration