Literature for a deeper understanding of the question of the work of DDE, ODBC and their connection with the SQL database?

Question

MySQL

Good afternoon.
It was possible to assemble the system, with the help of some kind of mother and swearing - the data from the OPC goes to MySQL and is read. But the process itself is a bit confusing.
Before that, I had never worked with databases, or with ODBC, or with DDE.
Who can guide you on the right path to search for information, so as not to be tied to a specific software, but to know exactly the technical points?
Literature/articles/links?
Preferably in Russian.