Query Xdata server

BIZ TMS XData
1

I have a table with 2 fields as primary key 

When i query the xdata server with http://localhost:2001/tms/xdata/ProductSpecs I am able to see the records but when I query it with details based on the first key with http://localhost:2001/tms/xdata/ProductSpecs(C001) it throws up
"error": {
"code": "EntityNotFound",
"message": "Requested entity does not exist."
}

How do I query Xdata in this case ?

How do I query Xdata in this case I need to retrieve based on both the keys >

2

The parenthesis syntax is only for the primary key, which is compounded by the two fields.

If you want to query by a different criteria (like for one of the fields belonging to the primary key), then you need to do a regular filter query, since it's not guaranteed that such query will return a unique record.
Use $filter query:
http://www.tmssoftware.biz/business/xdata/doc/web/filter.html