inst_key - ACCESS_KEY option
Special object instances can be referred to by setting an access key value in the data source. This information is provided for the application and not directly used by the data source. In order to locate a specific instance when opening the data source, an access key value or position should be set in accessKey.
Usually, this value is set in the configuration or ini-file in the INSTANCE option for the data source definition.
INSTANCE=P12345
Type: NString