Do we have any option to enable the online drc, which is usefull during layout design?
By "online" DRC I assume that you mean that checks are run during editing? If so, Cadence has the DRD feature, Design-Rule Driven editing which will give real-time feddback during editing to help ensure that layout constructs are DRC correct. Of course it will not be the same as a full DRC, nor can it replace the DRC checks, but it will help designers to create a layout with fewer (or no) DRC errors.
I hope that this is what you were asking and this answers your question.
Thanks for the info. DRD feature reads the DRC rule file defined by the PDK/Processes or some of the rules are inbuilt in the
DRD? Each process may have different drc rules and is there any way to make DRD to read all the drc rules defined by the process?
The information comes from the technology file within your technology library (in IC5141). There are various single and two layer rules that can be specified. In IC61, it comes from the constraints system - which may be (say) net specific, design specific, or technology specific - there are quite a rich set of physical constraints that can be specified.
Since this information is in the technology data, it will be process specific.
Of course, it is not quite as comprehensive as what can be encoded in a rule deck for a physical verification tool - because you can do extremely complex checks in such a tool. But it will allow you to cover a large proportion of the rules (particularly in IC61).