+ ()
+ (:documentation "Used to signal an error when the database
+cannot currently process a valid interaction because, for
+example, it is still executing another command possibly issued by
+another user."))
+
+(define-condition sql-timeout-error (sql-connection-error)
+ ()
+ (:documentation "Used to signal an error when the database
+times out while processing some operation."))
+
+(define-condition sql-fatal-error (sql-connection-error)
+ ()
+ (:documentation "Used to signal an error when the database
+connection is no longer usable."))