>What is the max length of characters allowed in a name of constraint?
>
>TIA.

128 characters.

Yes, see http://www.eggheadcafe.com/software/aspnet/32428002/length-of-index-and-const.aspx and
http://msdn.microsoft.com/en-us/library/ms186939.aspx

sysname is a system-supplied user-defined data type that is functionally equivalent to nvarchar(128), except that it is not nullable. sysname is used to reference database object names.