luxxi

#Using in single model
def self.update_or_create(attributes)
  obj = first || new
  obj.assign_attributes(attributes)
  obj
end
	
#User.where(email: "a@b.com").update_or_create(email: "d@e.com")

luxxi

Use COPY TO for dump the table data in csv format.

COPY table TO '/tmp/table.csv' DELIMITER ',';

Use the COPY FROM to "paste" it in another table.

COPY another_table FROM '/tmp/table.csv' DELIMITER ',';