Database design for 2 tables which are related by an id

Question

I am currently developing a tool which has the following tables and the respective columns.

Budget             Category          Transactions
budget_id          category_id       transaction_id
category_id                          category_id

Currently we are mapping the records of Budget to Transactions using category_id. But we have a glitch in the design. If two budget items have the same category_id, the transactions get mapped to both the budget. How can I have a design which maps the transactions items to the budget items in a one to one fashion but still keeping the loose coupling?

Answer 1

Budget             Category          Transactions
budget_id          category_id       transaction_id
category_id                          budget_id