When a situation arises to check a financial year like 200910, 201011, 201112 is in correct format, here is small tip to enforce a check constraint on a column in Oracle.
FinYear int check (finyear = floor(finyear/100)*100 + ( floor(finyear/100)-(floor(finyear/10000)*100)+1))
This will ensure that the input data is a valid financial year in format like YYYYyy (200910, 201011 ...).
This can be extended to any other database or language simply replacing floor function with appropriate language specific floor function. In most of the situations, floor function is directly supported by all major languages and databases.