The severity level of a message indicates information about the type and severity of the problem that Adaptive Server has encountered. For maximum integrity, when Adaptive Server responds to error conditions, it displays messages from sysmessages, but takes action according to an internal table. A few corresponding messages differ in severity levels, so you may occasionally notice a difference in expected behavior if you are developing applications or procedures that refer to Adaptive Server messages and severity levels.
WARNING! You can create your own error numbers and messages based on Adaptive Server error numbers (for example, by adding 20,000 to the Adaptive Server value). However, you cannot alter the Adaptive Server-supplied system messages in the sysmessages system table.
You can add user-defined error messages to sysusermessages with sp_addmessage. See the Reference Manual.
Users should inform the System Administrator whenever problems that generate severity levels of 17 and higher occur. The System Administrator is responsible for resolving them and tracking their frequency.
If the problem has affected an entire database, the System Administrator may have to use the database consistency checker (dbcc) to determine the extent of the damage. The dbcc may identify some objects that have to be removed. It can repair some damage, but the database may have to be reloaded.
For more information, refer to the following chapters:
dbcc is discussed in Chapter 25, “Checking Database Consistency.”
Loading a user database is discussed in Chapter 27, “Backing Up and Restoring User Databases.”
Loading system databases is discussed in Chapter 28, “Restoring the System Databases.”
The following sections discuss each severity level.