Two Solution:
1.If you want new record every time for booking than:
Add a column name like
BookingYear
. Now every-time user book cylinder new entry will be made with current date's year in this column. Now run following query before saving or booking:
Select * from table1 where BookingYear = '2014'
(like for the year of 2014).
Now if the Rows.count for this query is greater than equal to 9, than show message.
2.If you want 1 row for a year then add column to table like 'CylinderBookCount'. Every time user make a book uodate this table by increasing the amount in this column.
Now before booking cylinder add check like
Select CylinderBookCount from table1 where UserID = 'CopyOrAnyUniqueIDOfUser' BookingYear = '2014'
Now if this return column haveing value then greater than equal to 9, than show message.