A document data store manages the object data values and named string fields in documents.
The document key is a unique identifier for the document, often hashed for the even distribution of data. It helps in the retrieval of data from the document. In some document databases, the document key is created automatically while in others, you have to set an attribute of the document and use it as the document key.
Option A is incorrect. There is no primary key in the document of a document data store. The data is retrieved with the help of a unique identifier, document key.
Option B is incorrect. There is no hash key in the document of a document data store. The data is retrieved with the help of a unique identifier, document key.
Option C is incorrect. There is no secondary key in the document of a document data store. The data is retrieved with the help of a unique identifier, document key.
Option D is correct. The document key is a unique identifier for the document, often hashed for the even distribution of data. It helps in the retrieval of data from the document.
Reference: To know more about the Document Data Store, refer to the link below:
https://docs.microsoft.com/en-us/azure/architecture/data-guide/big-data/non-relational-data