Why does nvarchar(256) seem to the be the standard for user names in SQL Server?
Any system functions that return a user name return nvarchar(256), the ASP Membership provider uses nvarchar(256)
256 seems like an odd number (yes, I know its even...) - 255 I could understand (1 byte address) but 256 doesn't make sense to me.
Can anyone explain?
As programmers we automatically count starting at 0, but in this case nvarchar(0) would mean no characters. Turns out that 256 is your nice round number 2^8.
2^8 is 256, not 255.
Many times you will see numbering schemes from 0-255 which is 256 numbers when you include the 0.
Experience suggests that, across various database over a period of time, 256 seems to be the minimum value for the maximum length of string fields. I wouldn't be surprised if it goes back to dBASE.