Question

Can any one please explain the below simple statement

@object ||= ::Tablename.where (:fieldname => value ).first 

What is it mean and why || is used with = and :: is used before table name ?

Answer 1

The snippet checks to see if @object is false or nil; if it is, it assigns it the value produced by calling the method named Tablename in the top-level namespace.

This is because ||= means “assign if the value is currently falsey”; and :: is the scope resolution operator. Often it appears with a class name on the left, as in Net::HTTP accessing the HTTP constant in the Net module. Without a name on the left, it means “in the top-level scope”.