TLDR; I would like to get a warning on changing/adding a foreign key for Postgresql that it locks the table and if the table is large, it could be locked for some time. When adding or changing a ...

create table snapdeal_orders ( order_Id int not null, -- now we can not add null value in column order_id , not null constraint order_date date, -- "yyyy-mm-dd" is standard format product_name varchar ...