add constraint mysql code example

Example 1: alter table add column forigen key mysql

ALTER TABLE tryholpz_demo07.core_modules 
ADD COLUMN belongs_to_role INT, 
ADD FOREIGN KEY core_modules(belongs_to_role) REFERENCES role_specific_modules_info(id) ON DELETE CASCADE

Example 2: mysql alter add foreign key

ALTER TABLE ordenes ADD ticket VARCHAR(50) NOT NULL;
ALTER TABLE ordenes ADD CONSTRAINT fk_ticket FOREIGN KEY (ticket) REFERENCES tickets(ticket);

Example 3: mysql alter table set column unique

ALTER TABLE contacts
ADD CONSTRAINT contacts_unique UNIQUE (reference_number);