this is in SQL ,yes there is a reason as to why the month and year occupy the separate column,the two columns for month and year will be used to populate the effective_date column,the datetime can be in any format most preferable date-month-year.

@Esther - Not really answering the question here but why would you use two different columns to update the third as opposed to just populating it with the required date in the first place. 0_o?