SQL coding guidelines

SQL queries Zabbix components create/use must adhere to the following guidelines.


  • SQL statements should always be uppercase for the frontend code, and lowercase for server, proxy and database upgrade patches. This makes it easier to distinguish query source when debugging.
  • All column identifiers must be written in lowercase. This is required because, as opposed to other databases, PostgreSQL returns results with keys in lowercase.
  • Spaces should not be used around operators (comparison, mathematical, assignment, etc) or commas that separate fields or values. This reduces the amount of traffic to an SQL server.
  • Only single spaces should be used.
  • Inside a query, only spaces should be used, not tabs.
  • For a multi-line query, spaces should always be added at the beginning of a new line, not at the end of the previous one.
  • For PHP, table aliases should always be used, regardless of the number of tables involved in a query. For server and proxy, they are only used if more than one table is involved in a query.
    Specifically, in database patches:
    • If a table alter query changes only one property, it takes one line. If it changes multiple properties, each property (including the first) gets its own line.

Server SQL statements:

"select hostid,host from hosts where hostid=" ZBX_FS_UI64 " and status=%d;"
       "update hosts set host='%s',ip='%s',useip=%d where hostid=" ZBX_FS_UI64 ";"

All SQL parts in a multi-line query should have tree style

$sqlParts['where']['monitored'] = 'NOT EXISTS ('.
           'SELECT NULL'.
           ' FROM functions f,items i,hosts h'.
           ' WHERE t.triggerid=f.triggerid'.
               ' AND f.itemid=i.itemid'.
               ' AND i.hostid=h.hostid'.
               ' AND ('.
                   ' OR h.status<>'.HOST_STATUS_MONITORED.