Quoted identifiers are forwarded to remote servers that support them. This is triggered by a set command:
set quoted_identifier on
If this thread property is enabled, Component Integration Services quotes identifiers before sending SQL statements to remote servers.
Remote servers must have the ability to support quoted identifiers. There is a capability in the sp_capabilities result set reserved for this purpose:
Capability ID: 135
Capability name: quoted identifier
Capability value: 0 = no support; 1 = supported
The capability defaults to 0 for DirectConnects that do not provide a value for this capability.
