What do the following have in common Oracle OR db2 OR sybase OR "sql server" OR sqlserver OR informix OR mysql?

Oracle OR db2 OR sybase OR "sql server" OR sqlserver OR informix OR mysql OR "my sql" OR nonstop OR "sql/mx" OR "sql mx" OR sqlmx OR Cach� OR idms OR redbrick OR netezza OR interbase OR firebird OR postgresql OR "postgre sql" OR sapdm OR maxdb OR "sap dm" OR "max db" OR "SAPDB/MaxDB" OR "pervasive sql" OR "pervasiev sql" OR sqlbase OR "sql base",