How to implement a relational database?

Question

to select one database to select another

Answer 1

Okay, I hope I understood you correctly now, you want to select multiple fields from multiple tables, is that your question? well, if that's the case you can use JOIN in your query, I think it is covered in the lesson:

https://www.sololearn.com/learn/SQL/1865/

Answer 2

In a simple way, if your tables are connected one another through references you implement relational data. What do you mean "to select one database to select another"? I am not understanding your question here, can you explain?

Answer 3

when you select one database to select another

Answer 4

one table when selected, selects another table