Yes, I commonly use the yearmonth (YYYYMM) scenario. However, I use the fieldname TimeKey so as not to argue with the system about any reserved words. Additionally, I use an integer field in the table to allow queries easily to span segments that include differing years. The integer opens the door to arithmetic operations for query construction.

Example:

SequenceNumber TimeKey

11 201111

12 201112

13 201201

14 201212 & C.

In addition, I use the fields StartKey and StopKey (with a default 999999 on the second) as a handy way of identifying SCD lookups for historical data. This system is very useful when working with accounting systems where discreet monthly data is used.