Microsoft® SQL Server 2008 R2 Unleashed

Using CONTEXT_INFO

Although SQL Server enables you to define local variables within a T-SQL batch or stored procedure, local variables do not retain values between batches or stored procedures. Unfortunately, SQL Server 2008 does not enable you to create user-defined global variables. However, you can simulate global variables by using the CONTEXT_INFO setting, which allows you to store information in the context_info column in the sys.sysprocesses catalog view. A row in sys.sysprocesses exists for every connection to SQL Server, so the data remains there until you disconnect from SQL Server.

The context_info column is a binary (128) column. You can store any data value in it with the SET CONTEXT_INFO command, but you have to deal with hexadecimal ...