Question

I cannot seem to get this right, I am trying to modify a field to be a foreign key, with cascading delete… what am i doing wrong?

ALTER TABLE my_table 
ADD CONSTRAINT $4 
FOREIGN KEY my_field 
REFERENCES my_foreign_table 
ON DELETE CASCADE;

Answer 1

It would help if you posted the error message. But I think you are just missing the parenthesis:

ALTER TABLE my_table 
ADD CONSTRAINT my_fk 
FOREIGN KEY (my_field) 
REFERENCES my_foreign_table 
ON DELETE CASCADE;