Not sure about any tutorials. But, you can check below points.
Database table can be exposed as ODATA. You might need to create ODATA service with the help of ASP.Net
API logic needs to be written in the code.
Once ODATA service is ready, you can get the metadata xml and use the same to register in Datahub.
I could expose sample table from MySql as ODATA and registered in Datahub.