3.4.6. Manage Semantic Data Dictionaries

How semantic data dictionaries (SDDs) are created

There is one way of creating an SDD:

• by writing an SDD file as described in Section 5.4 and manually submitting the SDD file for ingestion as described in Section 3.2.1.

Hint: An SDD file, which is an spreadsheet file, can be entirely created outside of HADatAc using an ordinary spreadsheet editing tool like MS Excel, or entirely created inside of HADatAc using the SDD Editor of Working Files (See Section 3.3.2). For small SDD files (with 10 or less attributes), our recommendation is to develop SDDs inside of HADatAc because of the SDD Editor mechanisms to select terms and verify the SDDs. For larger SDD files, we understand that it may be more flexible to edit SDDs outside of HADatAc. In this case, our suggestion is the partially edit SDDs outside of HADatAc but still use the internal editor to select terms, and more importantly, to verify SDDs. In this hybrid scenario, the upload and download operations of Working Files should be used to switch editing environment.

Semantic data dictionary management operations

The figure below shows the data dictionary management page with two SDDs. The name and version of each SDD is shown along with the total number of attributes and objects specified inside the SDD.

For each existing SDD, the SDD management page supports the following operations:

• View SDD
• Delete SDD

View SDD

This view of the ingested SDD, i.e., as encoded inside of the knowledge graph. This is the exact view of the knowledge used to ingest data files that is inside of HADatAc's knowledge graph.

When compared against original SDD files, this view has the benefit of separating attributes from objects, and of replacing every available URI in the original SDD with its corresponding label.

Hint : Whenever possible, when showing SDDs, term URIs are replaced by labels. If no label is found for a given URI, the view will show the URI itself. Thus, the presence of URIs in the SDD view is a strong indication that one of the following two problems:

• the URI is not a valid term - it is not from a valid namespace, or it is a term that does not exist in the given namespace, or
• the knowledge required for loading the ontology is not available in the knowledge graph.

Delete SDD

The confirmation dialog below is shown before an SDD knowledge in the triple store is deleted. This option is not going to delete the corresponding SDD file from HADatAc processed folder. To deleted the SDD file, follow the procedure described in Section 3.2.3.