Choosing appropriate DataType in SQL Server table

Question

I have a large transaction table in SQL server which is used to store about 400-500 records each day. What is the data type should I use in my PK column? The PK column stores numeric values, for which integer seems suitable but I'm afraid it will exceed the maximum value for integer since I have so many records everyday.

I am currently using integer data type for my PK column.

Answer 1

With a type INT , starting at 1, you get over 2 billion possible rows - that should be more than sufficient for the vast majority of cases. With BIGINT , you get roughly 922 quadrillion (922 with 15 zeros - 922'000 billions) - enough for you??

If you use an INT IDENTITY starting at 1, and you insert a row every second, you need 66.5 years before you hit the 2 billion limit .... so with 400-500 rows per day - it will take centuries before you run out of possible values... take 1'000 rows per day - you should be fine for 5883 years - good enougH?

If you use a BIGINT IDENTITY starting at 1, and you insert one thousand rows every second, you need a mind-boggling 292 million years before you hit the 922 quadrillion limit ....

Read more about it (with all the options there are) in the MSDN Books Online .

Answer 2

I may be wrong here as maths has never been my strong point, but if you use bigint this has a max size of 2^63-1 (9,223,372,036,854,775,807)

so if you divide that by say 500 to get roughly the number of days-worth of records you get 18446744073709600 days-worth of 500 new records.

divide again by 365, gives you 50539024859478.2 years-worth of 500 records a day

so (((2^63-1) / 500) / 365)

if that's not me being stupid then that's a lot of days :-)