SQL

insert or update sql query

REPLACE INTO devices(id,name) 
VALUES 
   (4,'Central Printer')

update or insert sql

begin tran
if exists (select * from table with (updlock,serializable) where key = @key)
begin
   update table set ...
   where key = @key
end
else
begin
   insert into table (key, ...)
   values (@key, ...)
end
commit tran